FACTBOX: Facts about Palestinian group Hamas

(Reuters) - The Hamas Islamist movement has thousands of rockets and well-armed, highly motivated forces to deploy following Israeli air strikes in the Gaza Strip.

Here are some facts about Hamas:

CAPABILITIES:

* Hamas is believed to have thousands of short-range rockets, as well as scores of longer-range Grad rockets that could strike Israeli population centers up to 40 km (25 miles) from the border with the Gaza Strip.

* Hamas is believed to have a limited number of shoulder fired missiles that could be used against helicopters or slow moving planes, but has little defense against Israel's force of fighter jets, the most technologically advanced in the region.

* First deployed on the streets of Gaza in May 2006, Hamas's main security apparatus, initially dubbed the Executive Force, has grown from an estimated 3,000 members to more than 13,000, divided in several security branches. At least 180 of Hamas's security men were killed in Israel's air strikes.

* Hamas's main security force has grown since its takeover of the Gaza Strip in June 2007, in part because the Islamist group has money to pay salaries. The core of the force is mostly members of the Hamas armed wing, the Izz el-Deen al-Qassam Brigades, but it includes some members from allied militant factions such as the Popular Resistance Committees.

* The Qassam Brigades are believed to have 25,000 members but it is unclear how many of them overlap with other units.

* Well-armed and highly motivated, Hamas forces are equipped with assault rifles and grenades. Some wear body armor and carry anti-tank weapons smuggled into the Gaza Strip through tunnels from Egypt or manufactured locally.

* Israel and the United States say Iran provides funding and specialized training to Hamas units. Hamas is believed to have built some fortified bunkers modeled on those used by Hezbollah guerrillas in southern Lebanon.

* Hamas has called for a new uprising against Israel that would include suicide bombings in Israeli cities. With Gaza cordoned off, Hamas would be likely to turn to West Bank supporters, but many of them have been rounded up by Israel and Palestinian security forces loyal to President Mahmoud Abbas. Israeli security officials say the barrier the Jewish state is building in and around the occupied West Bank has made it harder to launch suicide operations from there.

TIMELINE

1987 - Hamas established during first Palestinian uprising.

1993 - Hamas rejects interim peace accords between Israel and Yasser Arafat's Palestine Liberation Organization.

1996 - Arafat elected Palestinian president. Fatah wins 68 out of 88 seats in parliament. Hamas boycotts the vote.

2000 - Second Intifada, or uprising, starts after the collapse of peace talks.

2004 - Arafat dies in Paris and is succeeded by Mahmoud Abbas as head of the PLO and Palestinian president.

2005 - Abbas and Israeli leader Ariel Sharon declare ceasefire. Abbas wins support from Hamas, which largely abides by the truce. Israel ends 38-year Gaza occupation.

2006 - Hamas wins Palestinian parliamentary election, taking 74 seats in 132-member parliament. Abbas's long-dominant Fatah movement wins 45 seats.

2007 - Hamas Islamists win brief civil war in the Gaza Strip against secular Fatah forces loyal to Abbas. Abbas sacks Hamas government and appoints his own in the Israeli-occupied West Bank.

WHAT IS HAMAS?

* Hamas is an acronym for Islamic Resistance Movement and also means "zeal" in Arabic.

* It is formally committed to destroying Israel and putting an Islamic state in its place. But Hamas has said it would accept a Palestinian state in lands captured by Israeli forces in the 1967 war in return for a long-term truce.

* Hamas has rebuffed demands from Israel, the United States and other nations to recognize the Jewish state and disarm. Israel and the United States have sought to isolate Hamas.

* Hamas spearheaded a suicide bombing campaign against Israel starting in 2000 but later abided by a 2005 truce. Israel's deadly air strikes in the Gaza Strip on Saturday prompted Hamas leader Khaled Meshaal to call for a new uprising.

* Hamas was helped in the 2006 parliamentary election by its pledges to eradicate graft in the Palestinian Authority and its fight against Israel. It is also popular because of a network of charities it runs.

(Editing by Timothy Heritage)