A bungled Israeli strike against a Hamas Members and a call by US President George Bush for the Islamic movement to be dismantled imperiled moves towards a truce deal with armed Palestinian factions. Following a new helicopter attack aimed at a wanted member from Hamas' armed wing, Islamic group promised retribution. "Faced by this aggression ... we cannot stay with our arms folded. We will hence answer, God willing, the crimes of the occupation," a statement said Thursday. Hamas also accused Israel of trying to scuttle truce efforts aimed at furthering progress on the roadmap, the international peace plan aimed at securing a separate Palestinian state by 2005. "This cowardly assassination confirms that the enemy does not want stability or quiet and hence puts real obstacles (in front of) our continuing inter-Palestinian dialogue and efforts towards a truce," senior official Ismail Haniya said. Its smaller rival Islamic Jihad warned that the strike would "negatively impact" on the ongoing discussions between Palestinian factions to agree on ceasefire proposals by Palestinian prime minister Mahmud Abbas. The dovish premier issued a statement which did not even mention the strike but nevertheless expressed concern over "Israel's stalling in the roadmap implementation." "If the roadmap is to succeed, Israel must immediately start carrying out its commitments, the same way the Palestinian Authority is," Abbas was quoted as saying. He also complained that Israel had postponed a security meeting on Tuesday night aimed at hammering out the final details of a deal for an Israeli withdrawal from designated reoccupied areas in exchange for the Palestinians taking over policing duties. As the Palestinians appeared to be on the brink of announcing a truce Wednesday night, an aggressive declaration by US President George Bush against Hamas was likely to further anger the Islamic group. He urged European leaders to take "swift and decisive action" against 'extremist' groups like Hamas by cutting off their sources of funding and support. "Progress toward this goal will only be possible if all sides do all in their power to defeat the determined enemies of peace, such as Hamas and other terrorist groups," he said. Israeli Foreign Minister Sylvan Shalom welcomed Bush's statement, saying that the US president "knows that without the dismantling of terrorist networks nothing is possible." "The Palestinians committed themselves in the roadmap to dismantling the infrastructure of the terrorist organisations and end incitements to hatred and violence," he told public radio, adding, "Over the past 10 years they have made many pledges which they have never kept." Sources from Palestinian leader Yasser Arafat's mainstream Fatah movement said the three main factions had drafted a proposal for a three-month truce last week. After two Fatah MP's travelled to Damascus for consultations with the exiled leadership of Hamas and Islamic Jihad, the sources said all sides had agreed on ceasefire covering Israel and the occupied territories. The proposal still had to be officially endorsed by the two radical groups' leaderships in the territories and approved by Arafat himself, but the sources added the factions opposed to the roadmap had committed themselves to not obstructing the political process. But Sharon said earlier in the week that Israel would continue to target militants he described as "ticking bombs" and neither side appeared ready to make the first step towards a reduction of the violence. Israeli troops on Thursday demolished the house of a jailed Hamas members in the southern West Bank city of Hebron, continuing a policy condemned by rights groups as collective punishment. **PHOTO CAPTION*** Palestinians carry the body of Eyad al-Masri, one of two Hamas members killed in an exchange of fire with the Israeli army in the northern Gaza Strip. (AFP/Mahmud Hams)