Six people were killed on Sunday when forces loyal to Palestinian President Mahmoud Abbas raided a Hamas hideout, just days after he promised in Washington to fulfil his security commitments. The violence erupted when police encircled a house in the West Bank town of Qalqilya where a top Hamas field commander, Mohammad Samman, and his deputy Mohammad Yasin had taken refuge, witnesses and security officials said. Both Hamas men and the homeowner died in the shootout, along with three policemen. Dozens of bullet holes in walls and furniture in the home attested to the ferocity of the fighting. It was the bloodiest internal Palestinian clash in the occupied West Bank since the Western-backed Abbas launched a security drive and revived peace talks with Israel in 2007 after breaking with Hamas over its takeover of the Gaza Strip. Samman and Yasin had ignored calls to surrender, witnesses said. Palestinian security forces spokesman Adnan Damiri said police had tried to negotiate a peaceful end to the standoff. “Thousands of shots were fired at the security forces,” Damiri said, adding that large quantities of explosives were discovered in the Hamas hideout. The raid was likely to widen a rift between Abbas's Fatah group and Hamas and complicate Egyptian reconciliation efforts. The operation also could boost Abbas's credentials in Washington at a time when US President Barack Obama is at odds with Israeli Prime Minister Benjamin Netanyahu over Jewish settlements in the West Bank. In the Gaza Strip, a spokesman for Hamas's armed wing accused the Abbas-aligned forces of being “loyal to the Zionists”. Abbas, the spokesman said, was directly responsible for “the crime and its consequences”. Obama hosted Abbas in the White House on Thursday and complimented him on security steps he has taken in the West Bank under the 2003 peace “road map” that includes a call for a crackdown on militants.