As Middle Eastern leaders gathered in Washington to inaugurate a new round of Israeli-Palestinian talks, Hamas gunmen killed four Israeli settlers in their car outside the West Bank city of Hebron.

The attack appeared to be an attempt to spark violence that could undermine the peace negotiations and was a stark reminder that the Islamist Hamas movement remains an important force in Palestinian politics, no matter how much either the Israelis or the Palestinian Authority's Mahmoud Abbas wish they would go away.

Analysts say that after more than a year of US diplomacy and an improvement in security in the West Bank, the summit in Washington won't be jeopardized by an isolated attack.

"The scale of it is not large enough and in terms of relations with America and the international community, the government of Israel is most likely to decide to continue," says Meir Javedanfar, a Tel Aviv-based Middle East analyst. "A future attack against Hamas will be more justifiable for Israel if Netanyahu stays in Washington. To break off the talks because of such an attack would be giving Hamas and their backers in Iran a major victory."

The attack came after Israeli Prime Minister Benjamin Netanyahu and Mr. Abbas had departed the region for the US talks.

Egyptian President Hosni Mubarak and Jordan's King Abdullah are also participating in the summit, which begins Wednesday night with a dinner hosted by President Obama.

Hamas takes responsibility

The shooting took place near the entrance of the Israeli settlement of Kiryat Arba, which neighbors Hebron. According to the Haaretz news outlet, those killed – four adults, including a pregnant woman – were from Kiryat Arba and the nearby settlement of Beit Haggai.

Hebron, a longtime flashpoint because it's home to a shrine holy to Jews and Muslims, is known as a relatively poor and conservative city where militant Hamas cells are believed to operate.

The Islamist Hamas movement, which controls the Gaza Strip, has repeatedly condemned the US-backed Palestinian Authority for agreeing to talks – calling instead to renew an armed uprising against Israel. Hamas claimed responsibility and heralded Tuesday's shooting, the first fatal attack on an Israeli in the West Bank since a police officer was killed in June.

"Hamas praises the attack and regards it as a natural response to the crimes of the occupation," Sami Abu-Zuhri, a Hamas spokesman in Gaza, was quoted by Reuters as saying. He added that the attack was proof "of a failure of security coordination" between Israel and the Palestinians.

That said, Palestinian security forces loyal to President Mahmoud Abbas have stepped up anti-militant activities throughout the West Bank in coordination with Israel. Increased Israeli-Palestinian security cooperation has led Israel to relax restrictions on Palestinian movement around the West Bank.

Attack on the peace talks

State Department Spokesman PJ Crowley speculated the attack was aimed at the peace talks, according to the Jewish Telegraphic Agency. Militants have timed attacks to coincide with peace summits in the past such as a terrorist bombing in Tel Aviv in February 2005, three weeks after a summit of Israeli and Palestinian leaders in Sharm el-Sheikh.

Israeli hard-liners said the attack was evidence that a peace deal is unrealistic and called on Prime Minister Netanyahu to boycott the summit. Education Minister Gideon Saar, a Netanyahu backer, said to abandon talks would be tantamount to rewarding the attacks, according to Haaretz.

Palestinian Authority media director Ghassan Khatib says Prime Minister Salam Fayyad is planning to issue a condemnation Tuesday night.

"I hope that the three parties involved make sure that they don't play into the hands of the attackers," he says. "The attack and its timing aims at sabotaging the peace process so the response should be to redouble efforts."