Hamas's June victory over Fatah in Gaza was more than a political achievement - it was a military bonanza. From its capture of Fatah's security headquarters, Hamas acquired stockpiles of American-made small arms and ammunition as well as a wide range of military equipment and vehicles originally transferred to bolster Fatah forces loyal to Palestinian Authority Chairman Mahmoud Abbas. In addition, increased smuggling since June has reportedly provided Hamas with additional Russian-made weapons, including antitank and antiaircraft missiles. The Shin Bet (Israel Security Agency) estimates that 40 tons of explosives entered Gaza in the two months following Hamas's takeover, along with 150 rocket-propelled grenade launchers in August alone. According to Public Security Minister Avi Dichter, it would have taken Hamas approximately one year - through smuggling or other means - to obtain the amount of weaponry seized during the Gaza takeover. Hamas's upgraded military capabilities will affect the durability of its control over Gaza, as well as Fatah's prospects for challenging that control, Israel's policy toward the territory, and future US security assistance to the PA. A survey of its arsenal supports the Israeli assessment that Hamas has undergone a "generational change" over the past two years. Small arms and antitank weapons Hamas displayed captured American arms on various affiliated Web sites and on its own Al-Aksa television network. It claimed to have captured thousands of M-16 and Kalashnikov assault rifles, along with large supplies of ammunition and stockpiles of RPGs, some equipped with dual warheads designed to penetrate armor. The group also possesses at least one Russian-made Dushka heavy machine gun that fires large-caliber rounds and can be mounted on vehicles. Although it is unclear whether Hamas acquired more advanced antitank missiles from Fatah or through smuggling, the group now reportedly has Sagger missiles that are more accurate and sophisticated than standard or upgraded rocket-propelled grenades. The group also reportedly possesses Russian-made Konkors antitank weapons capable of piercing armor. Antiaircraft missiles and rockets Numerous sources, including Chief of General Staff Lt.-Gen. Gabi Ashkenazi, believe Hamas has acquired antiaircraft munitions, including Strela (SA-7) missiles. Although IAF jets are equipped with systems to counter missiles, they may pose a threat to IDF helicopters and older aircraft. At the same time, however, these more advanced weapons will require a more sophisticated level of training on Hamas's part if they are to be effective. Hamas has also significantly increased its rocket capability. Following Israel's disengagement from Gaza two years ago, the group began to improve its Kassam rocket manufacturing capabilities. Since the weapons' introduction in 2001, their range has been expanded considerably from the original 2-3 kilometers. Hamas's newest Kassam rocket has an estimated range of 17 kilometers, capable of hitting Ashkelon. With wider tubes, these rockets can also carry a greater payload of explosives. In addition, Hamas has reportedly smuggled Katyusha rockets into Gaza. Both the Hamas-affiliated Palestinian Information Center and the Web site of Hamas's Izzadin Kassam Brigades acknowledged - but did not specifically confirm - Israeli reports that Hamas has acquired at least 50 long-range Katyushas. These rockets are more advanced than the homemade Kassams and are capable of striking targets up to 20 kilometers away. Hamas does not possess nearly as many of these rockets as Hizbullah, which launched up to 200 per day during its war with Israel last summer. Since June, Hamas has largely refrained from rocket fire against Israel while it concentrates on governing Gaza. Islamic Jihad, however, continues to actively plan and execute attacks against Israel. According to Jane's Defence Weekly, Islamic Jihad has surpassed Izzadin Kassam in rocket manufacturing and technology. The al-Quds Brigades - Islamic Jihad's military wing - recently unveiled its latest rocket, dubbed the Quds-4, with a reported range of 18-22 kilometers. Overall, Israel has reported 121 rocket attacks in the two months since Hamas's takeover. Captured Intelligence Hamas claims to have obtained thousands of hard-copy files as well as computer records, photographs, and audiovisual recordings from the Fatah-run PA intelligence headquarters. Although most US intelligence officials doubt that any highly sensitive material was compromised during the Gaza takeover, one former official with experience in the Strip told The Wall Street Journal in July: "People are worried, and reasonably so, about what kind of intelligence losses we may have suffered." In the same article, Bruce Riedel, an intelligence veteran and former National Security Council aide to Presidents Bill Clinton and George W. Bush, speculated that there would be "quite a treasure trove of materials that would document the relationship with the CIA." In Gaza, Hamas's former foreign minister Mahmoud Zahar told Newsweek the seized documents revealed global collaboration between Palestinian and US intelligence operatives. Zahar and other Hamas leaders are using the papers as part of an ongoing public relations effort portraying their Fatah rivals as collaborators with Israel and the West. Dichter and other Israeli officials believe Hamas has obtained eavesdropping equipment and other signals intelligence technology. This is a concern because Hamas could use such equipment to counter future efforts to monitor the group. Hamas's military organization Hamas is in the process of reorganizing its fighters into a more cohesive force. IDF officials say the group has approximately 13,000 armed members divided into four brigades. Hamas was apparently inspired by Hizbullah's war with Israel last summer and appears to be modeling its forces after the Lebanese Shi'ite militia. Israeli sources suggest that these changes are designed to help Hamas wage guerrilla warfare in the event of an Israeli invasion of the Gaza Strip, with a focus on maximizing casualties among IDF forces and nearby Israeli population centers. Hamas's Executive Force, the security unit established after group members were barred from integrating into the PA security apparatus, now numbers 6,000. Although its principal mission is to police Gaza, the force is also suspected of bolstering the Murabitun, Hamas's large popular army. Overall, Hamas is developing a diversified force capable of controlling domestic challenges and enhancing its capabilities against Israel. Since Israel's 2005 disengagement from Gaza - and especially since Hamas's more recent victory over Fatah - Hamas has significantly enhanced its military capabilities across a range of areas. This is likely to protect the group from domestic challenges for the foreseeable future as well as provide it with more options, both offensive and defensive, in the event of a confrontation with Israel. However effective the economic and financial blockade against Hamas may be, there is no sign that such efforts have dented the group's control over Gaza or slowed the pace of its military development. For now, Israel has opted not to initiate large-scale military operations in Gaza, wary of the casualties that would result. With last summer's war fresh in the public's mind, however, pressure could mount for Israel to act against Hamas before the group grows strong enough to replicate Hizbullah's performance. Under current conditions, a high-casualty incident - for example, a successful rocket strike on an Israeli target beyond Sderot - would likely provoke a harsh response. Nick Francona is a research intern at The Washington Institute.