BEIT JALLA, West Bank -- A Palestinian militant, whose clan has been targeted previously by Israeli security forces, was killed Sunday when a public telephone exploded in his hand -- one of six Palestinians to die in a day of violence, Palestinians said.

Mohammed Shtewie Abayat was speaking on the phone just outside the Beit Jalla Hospital near the West Bank city of Bethlehem when it blew up, killing him instantly, according to doctors. Relatives said he belonged to a militia linked to Palestinian leader Yasser Arafat's Fatah movement.

Palestinians blamed Israel, as they have when two other members of the Abayat clan were killed over the past two years. The Israeli military declined to comment. There were concerns that the killing of Abayat could lead some Palestinians to seek retaliation.

In other violence Sunday, Palestinians said a 4-year-old boy was fatally shot during what the Israeli army described as a firefight when troops entered the Rafah refugee camp to search for weapons smuggling tunnels in the southern Gaza Strip.

Also, the U.S. Ambassador to Israel, Daniel Kurtzer, sent a strongly worded message to Prime Minister Ariel Sharon's office over the weekend, saying Israel had not met promises to ease tough restrictions imposed on the Palestinians, a diplomatic source said.

The move comes as Sharon prepared to depart for the United States on Monday in advance of a Wednesday meeting with President Bush at the White House.

The Bush administration has strongly supported Israel in the Mideast conflict, especially in recent months.

Ease grip

However, Kurtzer's letter called for Israel to ease its military grip on the West Bank Palestinian cities it occupied after suicide bombings in June, allow Palestinians greater freedom of movement and turn over withheld taxes that Israel collected on behalf of the Palestinians, according to the diplomatic source and Israeli newspapers.

Israel's Cabinet on Sunday discussed the possibility of removing some military blockades in and around Palestinian areas and handing over the tax money.

Cabinet Secretary Gideon Saar said no decision was taken, and Israel's response would depend on cessation of Palestinian attacks. He said the subject would be on the agenda when Sharon and Bush meet.

In Beit Jalla, Abayat's brother Moussa said the two had brought their mother to the hospital and 28-year-old Mohammed went outside to use the public telephone. He "started to speak on it and it suddenly blew up. Parts of his body were everywhere," Moussa Abayat said.

"I believe it is an assassination of my brother," he said, adding that his brother was a member of the Al Aqsa Martyrs Brigade, which is linked to Arafat's Fatah movement.

Israel has carried out dozens of targeted killings against militants suspected of violence against Israelis. Israel has acknowledged carrying out many attacks, though in some cases, it has refused to confirm or deny involvement.