OCCUPIED JERUSALEM, 20 June — The fragile Israeli-Palestinian cease-fire tottered precariously yesterday, amid pessimistic assessments from Israeli officials that it was on the point of collapsing one week after it came into being. Israel said it had begun reassessing nearly a week-old cease-fire at security meetings yesterday.

“We’re reassessing the overall cease-fire because of the continuing violence,” said Raanan Gissin, spokesman for the hawkish Prime Minister Ariel Sharon. He said the reassessment had begun yesterday and would resume today at a security Cabinet meeting. Both sides last week agreed to a truce mediated by US CIA Director George Tenet to end nearly nine months of violence.

In Madrid, Palestinian President Yasser Arafat said Jewish settlers, living on land Israel occupied in the 1967 Middle East war, were responsible for the violence. “We do not commit acts of violence,” he told a news conference. “The violence today is committed by the settlers... Regrettably, some Israeli forces, not all of them, protect these settlers.”

Arafat, who met Spanish Prime Minister Jose Maria Aznar and then held a joint news conference, renewed his call for more international observers, saying calm has returned to areas where they are stationed. Aznar backed Palestinian demands for Israel to halt Jewish settlement building in the occupied West Bank and Gaza.

Israeli Foreign Minister Shimon Peres met European Union ambassadors in Jerusalem and said the Palestinians had violated the cease-fire more than 50 times since it began. “The situation is very serious and I think all parties have to make a major effort, particularly the Palestinians, to save the cease-fire from falling apart,” he told reporters.

Ahmed Abdel-Rahman, a senior aide to Arafat, called for an international force to determine who was breaking the truce. “Sharon is waging a fierce campaign on the Palestinians. Instead of lifting the siege and adhering to the cease-fire, we see him strangling the Palestinians and encouraging extremist settlers to sabotage Palestinian properties,” he said.

With pressure mounting in Israel on Sharon, the army dug at least three trenches around Tulkarem and tightened blockades on Nablus and Jenin, all cities in the West Bank, witnesses said. It also built trenches around the town of Tubas. Israeli and Palestinian security officials were due to meet today, joined by US officials, to set a timetable for the army to completely lift its blockade, which has severely hurt the fragile Palestinian economy.

A 16-year-old Palestinian, Adel Al-Moganen, died overnight of wounds sustained on Sunday, said hospital officials in Gaza. In that incident, the Israeli Army said troops had fired at Palestinians.