JERUSALEM (AP) – A sudden spike in Israeli-Palestinian violence threatened a period of calm that has surrounded Israel”s pullout from Gaza and part of the West Bank as well as a six-month truce, leading to calls for restraint from the United States.

On Thursday, Palestinian leader Mahmoud Abbas blamed Israel for the upsurge, calling a raid on a refugee camp in which Israeli forces killed five Palestinians an intentional provocation. Israel said the raid was necessary to stop Palestinian attacks because Abbas” forces were not doing their job.

Following Tuesday”s completion of the most important stage of the Israeli pullout, emptying 25 settlements, violence flared in three places.

On Thursday, a rocket fired from Lebanon exploded in an Israeli village just across the border, causing some damage but no casualties. Late Wednesday, Israeli forces raided the Tulkarem refugee camp in the West Bank, killing five Palestinians, at least three of them armed. A few hours before that, a Palestinian stabbed two young Jewish men in the Old City of Jerusalem, killing one and seriously wounding the other.

The United States urged restraint. &#34We always denounce any violence and we urge both sides to exercise calm,&#34 said White House spokesman Trent Duffy, speaking from Crawford, Texas, where U.S. President George W. Bush is vacationing at his ranch.

U.S. State Department spokesman Sean McCormack said both sides should &#34refrain from actions that could inflame tensions.&#34 McCormack also noted, &#34As we have said before, Israel has a right to defend itself.&#34

Abbas blamed Israel for the sudden escalation with its deadly West Bank raid. &#34This murder intentionally aims at renewing the vicious cycle of violence,&#34 he said.

Raanan Gissin, an aide to Israeli Prime Minister Ariel Sharon, responded that the Palestinians have failed to control the militants. &#34We have transferred authority over this city of Tulkarem and the surrounding villages to the Palestinian Authority, and over a period of about three months, no action has been taken,&#34 Gissin said. Since Abbas and Sharon declared a cease-fire in February, the number of violent incidents has dropped drastically. However, both Hamas and Islamic Jihad have carried out attacks, claiming they were responding to Israeli violations.

Islamic Jihad sent a suicide bomber into Tel Aviv in late February and another into Netanya in July. Five Israelis were killed in each attack. The cell”s leadership was traced to the Tulkarem area, and Israel has been hunting its members, claiming that even under the truce, it has the right to take defensive measures.

Israeli Defense Minister Shaul Mofaz said the intention was to arrest the fugitives. &#34This was an operation against a ”ticking bomb,”&#34 he told Israel TV. &#34They were planning a suicide bomb attack in Israel.&#34 Hamas, Islamic Jihad and the Al Aqsa Martyrs” Brigades vowed revenge. &#34The Zionists should prepare … bags to collect the remains of their soldiers and settlers because we are going to hit in the depths of the entity,&#34 said Abu Abdullah, an Islamic Jihad commander in the Gaza Strip.

Hours later, militants fired two homemade rockets from Gaza into southern Israel, the army said, the first such attack since Israel began its pullout from Gaza on August 15. There were no injuries or damage. A local militant group said the rocket fire was in retaliation for the Tulkarem raid, Israel Radio reported.

After sunset, hundreds of Islamic Jihad militants marched in Gaza City and Khan Younis, pledging revenge.

At midday Thursday, a rocket fired from Lebanon exploded in Margaliot, an Israeli farming village on the border. The rocket damaged a chicken coop, but no one was hurt. Israel Army Radio reported it was the first time such a rocket has been fired at an Israeli community since Israel ended its 18-year occupation of south Lebanon in 2000.

Israeli security officials have been warning that militant groups in Lebanon might try to heat up the border area during Israel”s pullout from Gaza and part of the West Bank.

The Jewish seminary student killed in the Jerusalem stabbing attack was buried Thursday. He was identified as Shmuel Matt, 21, a British citizen. A second student, Sammy Weissbard, 20, from New York, was wounded.