Leaders of more than a dozen of Palestinian armed groups, who gathered for a meeting in the Gaza City, told a news conference they would step up attacks against Israel to frustrate the ongoing direct Israeli-Palestinian peace talks. "The factions agreed that all means are open to the Palestinian resistance to deal with Israel in the coming phase," the factions said in a statement read by a spokesman of a Hamas armed wing. A total of 13 armed groups, including the Islamic Jihad movement, the Popular Front for the Liberation of Palestine (PFLP) and the Democratic Front for the Liberation of Palestine (DFLP), took part in the conference. Four Israelis, including a pregnant woman, were shot dead in the West Bank on Tuesday. The armed wing of Hamas said it was responsible for the killing, calling it "a response to the crimes of the occupation". U.S., Israeli, and Palestinian delegations held trilateral discussions in the U.S. Department of State on Thursday, followed by a smaller meeting of Israeli Prime Minister Benjamin Netanyahu, Palestinian President Mahmoud Abbas, U.S. Secretary of State Hillary Clinton and U.S. Special Envoy for Middle East Peace Process George Mitchell. The Israeli and Palestinian leaders then went into a separate meeting for a direct discussion, their first direct negotiations in 20 months.