Israeli Army troops began moving into the northern Sinai Peninsula early today to remove forcibly 2,000 nationalist settlers after the Cabinet postponed until Wednesday a final decision about returning the territory to Egypt on April 25 as scheduled.

Deputy Secretary of State Walter J. Stoessel, on a diplomatic mission to iron out last-minute disputes over the withdrawal, arrived in Jerusalem last night from Cairo carrying assurances from President Hosni Mubarak that Egypt's "firm adherence" to the Camp David peace process would continue after the return of the Sinai. Stoessel met for two hours with Prime Minister Menachem Begin, but neither side would comment afterward.

The delicate diplomatic maneuvering came amid escalating threats by settlers opposed to the withdrawal, some of whom vowed to commit suicide rather than submit to eviction from their Sinai redoubts.

Begin told his Cabinet yesterday that the government will wait until a special Cabinet meeting on Wednesday to decide formally on the scheduled turnover of the last third of the Sinai, a move that fueled speculation about a last-minute delay.

There are a number of outstanding Egyptian-Israeli disputes about border demarcations and deployment of troops within demilitarized zones. Israeli officials also are insisting that Egypt sign a new tripartite declaration with Israel and the United States reaffirming its commitment to the Camp David peace process.

Egyptian Foreign Minister Kamal Hassan Ali is due in Jerusalem Wednesday for an expected final round of negotiations on the proposed declaration, which Israeli sources say Stoessel has agreed to in principle but which Egyptian officials reportedly are resisting.

Moshe Arens, Israel's ambassador to the United States, sought Sunday to defuse speculation that his government might back out of the Sinai withdrawal. Appearing on ABC-TV's "This Week With David Brinkley," (WJLA) Arens said, "I think there is every reason to believe the Cabinet will reaffirm that April 25 is the date on which Israel will withdraw . . . ."

Despite the appearance of a diplomatic standoff between Israel and Egypt, hundreds of Israeli troops assembled at an Army base adjacent to this border kibbutz early this morning for a large-scale evacuation operation scheduled to begin before dawn.

Shortly before midnight, trucks filled with soldiers roared out of the base and crossed the border in the direction of Yamit, the Mediterranean settlement about eight miles southeast of here, where most of the holdout opponents to the Sinai withdrawal have been preparing for a confrontation.

The evacuation was ordered by Defense Minister Ariel Sharon shortly after yesterday's Cabinet session.

Army Brig. Gen. Chaim Erez, commander of Israel's southern district, said he hoped that bloodshed could be avoided, despite threats by some of the most zealous settlers to make a "last stand."

"The evacuation is not war and the people being evacuated are not the enemy. This fact has been made sufficiently clear to all the soldiers taking part in the operation. I just hope that the squatters will not use their children to help resist the Army," Erez said.

Children of the militant members of the "Stop the Sinai Withdrawal Movement" have been used for several days to prevent the dismantling of equipment in the northern Sinai. Some have sat down on water lines that were to have been ripped up and others have gathered to play in front of bulldozers used to tear down structures and plow under the crops left behind at agricultural settlements around Yamit.

Among the troops assembling here were scores of women soldiers assigned to remove women and children forcibly from the houses they occupied after the original settlers left Yamit weeks ago.

Leaders of the resistance group estimated that more than 3,000 protesters are in Yamit, although the Army Command in Tel Aviv put the figure at closer to 2,000.

Army officials said that it may take two to three days to complete the evacuation if there is resistance.

Most of the squatters have said they will offer only passive resistance to the Army, but about two dozen members of the extremist Jewish Defense League, headed by U.S.-born Rabbi Meir Kahane, have claimed they will fight the troops, and some of them have vowed to commit suicide if the Army tries to remove them. Most of these are Americans who arrived here in the last few weeks to protest the Sinai withdrawal.

Speaking from behind a locked door to an underground bomb shelter next to a Yamit motel, the JDL members said they were awaiting Kahane's return from New York before going ahead with their suicide plan. They said they already had decided in which order they would die.

Other militants have barricaded themselves atop the towering spirals of a concrete war memorial erected for Israeli soldiers who died in the Yamit region in the 1967 Six-Day War. They have surrounded themselves with barbed wire and booby traps, and reportedly have a cache of gasoline-filled bottles with which to fight off the security forces.

The Army Command sealed off the border to journalists last night, saying that reporters and cameramen would inflame the situation and lead to more violence. The Army said reporters and photographers already inside Yamit were being ordered out, and that any journalists caught inside would be arrested and detained for 36 hours. Officers at the border said the press ban had been ordered at the "highest levels of the government."

Washington Post correspondent David Ottaway filed the following report Sunday from Cairo:

While President Mubarak restated his commitment to the peace accords, Egyptian officials also made clear that they are not willing to sign a new declaration or treaty addendum promising to respect the accords, as the Israelis reportedly are asking.

The Israeli demand, coupled with complaints of alleged Egyptian treaty violations, have created concern here that Israel is seeking a pretext to delay its withdrawal.

But after two days of listening to Egyptian views, U.S. envoy Stoessel told reporters today that he remained confident that existing problems would be overcome and that the withdrawal would take place on time.

He also said Mubarak assured him of Egypt's "firm adherence to the Camp David accords as the only existing basis and framework on which to proceed in the search for a just, lasting and comprehensive peace in the area."

But the semiofficial Al Ahram newspaper reported that Foreign Minister Ali told Stoessel that Egypt felt there was no reason for another formal document recommitting it to accords already ratified by the two countries' parliaments.

He also was said to have rejected an Israeli demand for an Egyptian commitment not to deal with the Palestine Liberation Organization, pointing out there is a PLO office in Cairo with which the government long has had dealings.

Stoessel indicated that his travels between Egypt and Israel probably would continue with more talks here after his meeting with Begin. U.S. officials said privately that Stoessel was committed to staying in the area as long as necessary to ensure the Israeli withdrawal.

The Egyptians have forwarded to Israel their views on how arbitration should proceed over the unresolved demarcation of the border around Taba on the Gulf of Aqaba as well as how the disputed one-quarter square mile of land should be administered pending final resolution of ownership.