QALQILYA, West Bank, (Reuters/AFP) - Six people were killed in a West Bank shootout on Sunday when an attempt by forces loyal to Palestinian President Mahmoud Abbas to arrest a senior Hamas commander went awry, deepening the rift between the two main factions. The movement ruling the Gaza Strip warned that the rival Fatah group loyal to President Abbas had crossed a red line over the killing of one of its top fighters in the arrest operation. 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. 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. In the Gaza Strip, a spokesman for Hamas 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. The movement branded the incident a red line and said it laid complete responsibility of this ugly crime on Abbas and his security forces. Describing Abbas and his forces as agents of arch-enemy Israel, Hamas said in a statement that it would respond with acts, without elaborating. There is no difference between the occupation who shoots and the people who carry out their missions for them, a spokesman for Hamas armed wing said at a Press conference in Gaza. Hamas spokesman Fawzi Barhum said there was no chance of further reconciliation talks with Fatah after the escalation by security services of Abu Mazen and Fatah against Hamas and its leaders in the West Bank. Fatah should choose - dialogue with us or doing the dirty work of the Zionist enemy, Barhum said as Hamas decried the killing over mosque loudspeakers in Gaza City. A senior official from the Fatah-led Palestinian Authority dismissed the Hamas accusations as lies. The Palestinian Authority has one duty to impose security and the law and we will not allow what happened in Gaza to happen here in the West Bank under any circumstances, he said on condition of anonymity. A spokesman for Palestinian security forces, Adnan Damiri, defended the arrest operation. We in the Palestinian security branches are not a political force. We are security. We will not allow any Palestinian party to have guns and threaten civilians. Damiri also said that during the arrest, police discovered Hamas leaflets containing incitement against the Palestinian Authority and against the Palestinian security branches. We consider what happened today as very dangerous, he said. It was an attempt to destroy any hope of resuming the (reconciliation) dialogue. It was not immediately clear if US-trained forces took part in the Qalqilya operation.