Refusing an Israeli demand to delay and change a U.N. team that will investigate Israel's assault on the Jenin refugee camp, Secretary-General Kofi Annan on Tuesday night directed the team's members to arrive in the Mideast by Saturday.

Arab nations have accused Israel of massacring Palestinian civilians in the camp, but Israel says the deaths and destruction resulted from gunbattles between its soldiers and Palestinian gunmen. The fighting in Jenin was the fiercest of Israel's 3-week-old military offensive.

The U.N. Security Council held emergency consultations Tuesday night after Israel suddenly announced it was delaying the fact-finding mission.

Israel's U.N. Ambassador Yehuda Lancry said Israel wanted more military and counter-terrorism experts added to the team, assurances it would confine its activities to Jenin, and an investigation of Palestinian terrorist activities in the refugee camp.

While the council was holding consultations, Lancry met Annan in his 38th floor office at U.N. headquarters to ask for changes in the team's composition and its scope of action.

Annan would not discuss his choice of team members, though he did not rule out adding additional experts if necessary, a statement from the U.N. spokesman said.

The secretary-general said the mandate of the team was the Security Council's resolution adopted unanimously last Friday which welcomes the fact-finding mission. It also expresses concern at "the dire humanitarian situation of the Palestinian civilian population," especially in Jenin.

At the end of a nearly two-hour meeting, the council issued a statement saying it expects "fast implementation" of Friday's resolution — and Israel's "full cooperation" with the secretary-general and the team.

Israel asked to send representatives to brief U.N. officials "to make sure that the government's point of view was understood," and they could arrive on Thursday, the U.N. statement said.

The secretary-general agreed to postpone the departure of the fact-finding team to allow those consultations, "but he expects the team to be in the Middle East by this Saturday."

Former Finnish President Martti Ahtisaari, leader of the fact-finding team, went ahead with his scheduled flight to Geneva on Tuesday night, where he will meet other team members. He said earlier that he expected to reach the region by the end of the week.

An Israeli official in Jerusalem charged that the team was chosen by Annan without consulting Israel, as had been agreed, and the members were political, not from a military background as Israel had requested.

A Western diplomat said Israel wanted to negotiate terms for the team's activities in Palestinian areas, and wanted one member removed, Cornelio Sommaruga, former president of the International Committee of the Red Cross.

Israel has had a difficult relationship with the United Nations, which once had a resolution on the books equating Zionism with racism. Relations improved under Annan but were strained again last year after the United Nations admitted it misled Israel about potential evidence in the kidnapping of Israeli troops in south Lebanon. Recent remarks made by Annan's envoy to the Mideast over the Jenin operation infuriated the Israeli government.

Problems with the International Committee of the Red Cross — which Sommaruga headed from 1987 until 1999 — have been continual since Israel was first rejected for membership in the organization in 1949. The ICRC recognizes only the Cross and the Muslim Crescent as official emblems and will not sanction the Jewish Star of David as a symbol for relief workers.

Israeli Foreign Minister Shimon Peres gave a green light to the fact-finding mission on Friday saying the country had "nothing to hide."

After meeting Annan, Lancry told reporters "Israel is ready to cooperate with the fact-finding team." But he said Israel "is looking to get a more balanced team," and to ensure that "the focus will be Jenin and not other areas."

Israeli Defense Minister Binyamin Ben-Eliezer on Monday night demanded that retired U.S. Maj. Gen. William Nash, who was appointed as military adviser, be made a full member of the team because of the complex security issues involved — a demand Lancry reiterated.

Annan is sticking with his three-member team — Ahtisaari, Sommaruga and Sadako Ogata, the former U.N. high commissioner for refugees.

But Ahtisaari stressed that Nash would play "a crucial role" and the entire mission — which will number about 20 with advisers, administrative and security personnel — would act as a team.

Neither Annan nor Ahtisaari ruled out the possibility of going outside Jenin.

Nasser Al-Kidwa, the Palestinian U.N. observer, called the Israeli decision to seek a delay "blatant blackmail which will definitely undermine the integrity of the fact-finding process."

"We thought that the Israeli side did not have anything to hide, but obviously they do," he said.

Al-Kidwa said he initially asked for the council meeting after explosions in the Ramallah compound where Arafat is besieged by Israeli troops and tanks, which he called "a very dangerous development."

The Security Council statement Tuesday expressed "serious concern" for Arafat's safety and "stressed that there must be no harm to him or others in the compound together with him," and reiterated that the siege must be lifted.

The Associated Press contributed to this report.