After playing a key role in the group’s military development for years and navigating deep ideological rifts, Tehran has renewed its extensive sponsorship in ways that contributed directly to the recent bloodshed in Gaza.
When the dust settled from the latest Gaza showdown, Hamas and other militant groups had killed more Israeli civilians than the entire fifty-day war of 2014, firing nearly as many rockets but concentrated in just one-fifth the time. On May 21, Hamas political bureau chief Ismail Haniyeh praised Iran for enabling this intense bombardment, noting that Tehran “did not hold back with money, weapons, and technical support.” Five days earlier, while the fighting was still in full swing, the Iranian pro-regime outlet Tasnim News reported a phone call in which Esmail Qaani, head of the Islamic Revolutionary Guard Corps-Qods Force (IRGC-QF), spoke with Haniyeh and lauded Hamas’s actions. This message was echoed by other major Iran-backed militant groups, including Lebanon’s Hezbollah, Iraq’s Kataib Hezbollah, and Yemen’s Houthis. Far from being an isolated phenomenon, the exchange of praise reflects a years-long warming of relations between Iran’s “axis of resistance” and Hamas, despite their Shia/Sunni ideological differences.
The Development of Hamas-Iran Relations
After emerging in the 1980s as a Sunni jihadist offshoot of Egypt’s Muslim Brotherhood, Hamas drafted a formal charter that enshrined the goals of destroying Israel and fighting “the warmongering Jews.” The group later began developing high-level contacts with Iran when the Islamic Republic convened two conferences on Palestine in . Attended by Hamas delegates, this forum became a counterweight to the ongoing Arab-Israeli peace process and the 1991 Madrid conference.
Around this time, the group gained prominence by participating in the Palestinian intifada against Israel, prompting Yitzhak Rabin’s government to deport 418 leading Hamas figures to Lebanon in 1992. The IRGC and Hezbollah (created by Iran the previous decade to resist the Israeli occupation of southern Lebanon) hosted the Hamas deportees and taught them how to build and use suicide bombs, a tactic pioneered by Hezbollah. When Rabin permitted the deportees to return, Hamas and other Gaza-based groups quickly began conducting suicide bombings against Israel, while Iran began sending the group up to $50 million annually.
The IRGC, Hezbollah, and Hamas continued cooperating through the second intifada ( ). Hezbollah made three major attempts to smuggle weapons and bombmakers into Gaza during this period; it also helped Hamas build the extra-potent weapon used in a March 2002 suicide bombing that killed thirty Israeli civilians. In this way, Hamas developed not as a full Iranian proxy like Hezbollah, but rather as a pragmatic partner to Tehran’s anti-Israel axis.
The relationship was further strengthened by Iran’s efforts to foster the Hamas rocket program. In 2014, IRGC missile commander Ahmed Hosseini disclosed that years earlier, Hamas operatives had been “armed and trained by Hezbollah…Some of them even came to Iran for training.” He specified that the architect of Iran’s own missile program, IRGC general Hassan Tehrani Moghaddam (now deceased), was the one “who armed them and guided them.”
Initially, the IRGC and Hezbollah taught Hamas engineers how to make rockets from everyday materials such as sugar and pipes, enabling the group to begin domestic production of its mainstay short-range rocket, the Qassam. Following Israel’s 2005 withdrawal from Gaza and the subsequent Hamas takeover there, the group began collecting unexploded Israeli ordnance for rocket production. It also received more-advanced rockets from Iran and Syria. Several Iranian arms appeared in the Gaza conflict; by the time of the 2012 conflict, Hamas was launching long-range Iranian Fajr-5 rockets at Tel Aviv and Jerusalem. Iran’s influence was also evident in the parallel evolution of Hamas and Hezbollah’s modus operandi following Israeli withdrawals from their respective territories—namely, from suicide terrorism (made more difficult by the construction of Israeli security barriers) to rocket, mortar, and antitank ambush attacks, all supplemented by tunnels and civilian human shields to evade retaliatory airstrikes.
To supply Hamas with such materiel, Iran developed various smuggling routes. In some cases, Sinai-based Bedouin smugglers brought items to Gaza via Sudan, with the approval of Islamist president Omar al-Bashir. Yet Bashir expelled Iranian officials from Sudan in 2014, mainly in the hope of staving off economic collapse by winning financial aid from Tehran’s regional archrival Saudi Arabia. Iran and Hezbollah have also smuggled weapons and rocket manufacturing materiel by sea, evading the Israeli blockade by dropping floatable items for Palestinian fishermen to pick up near the Gaza coast. Even the Islamic State began helping with arms smuggling via its Sinai “province”—according to Egyptian and Israeli intelligence sources, the group was willing to set aside its ideological hostility toward the “apostate” Muslim Brotherhood-linked organization in exchange for Hamas weapons and training.
At the same time, however, the outbreak of the Syria war in 2011 soured Hamas-Iran relations, since Tehran supported the Assad regime and Hamas backed the Sunni Arab opposition. Hamas further strained the relationship by voicing support for Saudi Arabia during the Gulf coalition war against the Iran-backed Houthis. Iranian and Hamas officials still held quiet high-level meetings from time to time, and Tehran was quick to express support for the group during any Palestinian flare-ups with Israel. Yet Iran reduced or possibly halted its funding to Hamas.
The group found numerous ways to make up for the lost Iranian money. It turned to Turkey and Qatar for direct financial support. Moreover, when Libya’s civil war broke out in 2011 and for years afterward, local and Israeli officials warned that Hamas was working with Libyan weapons smugglers. In June 2012, for example, Egyptian security forces confiscated 138 Grad rockets brought in from Libya and destined for Gaza. Hamas also leveraged its improving indigenous capabilities by repurposing civilian humanitarian assistance arriving from Israel for military purposes (e.g., using wooden panels and engines for tunneling and bombmaking).
In 2017, Tehran mediated a reconciliation between the Assad regime and Hamas, building on the group’s appointment of a more Iran-friendly leader, Yahya al-Sinwar. These developments greatly renewed Hamas-Iran relations—in August of that year, Sinwar proclaimed that the Islamic Republic was its “largest backer financially and militarily.” Iranian officials have since boasted about their role in upgrading the group’s capabilities. In January 2021, IRGC Aerospace Force commander Amir Ali Hajizadeh stated, “All the missiles you might see in Gaza and Lebanon were created with Iran’s support.” This includes transfers by sea and apparent deliveries from Libya—earlier this year, intelligence officials in that country warned that Iran is now involved in smuggling weapons to Gaza via Libya (Turkey and Qatar were implicated as well).
Hamas’s augmented operational and production capabilities reflect this renewed Iranian support. The Israel Defense Forces estimated that Hamas and other Gaza groups possessed up to 15,000 rockets at the outset of the latest fighting. By basing domestically produced rocket designs on Iranian models, Hamas has upgraded its arsenal with enhanced accuracy, longer range, heavier warheads, and improved launchers like the A-120. In addition, it produced and used at least six Shahab kamikaze drones that strongly resemble Iran’s Ababil model. Such capabilities enabled it to maintain frequent barrages of up to twenty-seven rockets per minute against targets as distant as Tel Aviv, in line with the goal of overwhelming Israeli missile defenses and causing higher casualties. According to Maj. Gen. Ori Gordin, the head of Israel’s Home Front Command, the country witnessed the highest-ever rate of rocket fire into its territory.
Meanwhile, Iranian proxies around the Middle East voiced substantial praise and offers of military support for Hamas during the latest clash. On May 16, Abu Azrael, the commander of Iran-backed militia Kataib al-Imam Ali, announced that some Iraqi personnel “were deployed” to join the fight against Israel (though he did not disclose where). And in a May 25 speech, Hezbollah chief Hassan Nasrallah hailed Hamas actions as a “historic step in the conflict with the enemy,” portraying the group as an important part of the resistance axis.
Iranian sponsorship played a major role in enabling Hamas to start last month’s fighting in Gaza. When the territory eventually moves toward reconstruction, the Biden administration should help ensure a strict monitoring mechanism—complete with in-person supervision of imports—to prevent Hamas from rearming. This will be difficult because the group has been known to build rockets from seemingly innocent materials. Cracking down on smuggling along the Gaza border is important too, as is working with Egypt to prevent the transfer of materiel via Libya or Sudan.
Another way to degrade Iranian support for Hamas is to counter Tehran’s growing influence in the wider Middle East. The Biden administration can assist in this respect by helping Arab states and Israel forge additional normalization agreements, which would put each party in a better position to cooperate on counterterrorism, anti-smuggling, and other efforts to curtail destabilizing Iranian activities. Any country facing heavy Iranian encroachment would be a good candidate for such efforts, particularly Iraq, Saudi Arabia, and Oman.
Ido Levy is an associate fellow with The Washington Institute who specializes in military and counterterrorism operations, particularly relating to jihadist groups.