JERUSALEM, FEB. 6 -- Official Israeli sources said today that U.S. and allied forces have destroyed about 600 Iraqi tanks and that at least one division of the elite Republican Guard has been badly mauled in bombing raids.

According to the Israeli sources, Iraq has moved its remaining mobile Scud missile launchers in western Iraq to the area of Kayam, about 40 miles northwest of a site designated "H-3" by the military, where some of the missiles originally were based.

This, the officials said, explains in part why Iraqi missile attacks on Israel have been largely ineffective in the last 10 days and none have been fired since Saturday.

Israeli assessments also show that 40,000 tons of an estimated 300,000 tons of Iraqi ammunition stocks have been destroyed in allied air raids.

Official sources said the relentless bombing has caused Iraqi commanders to disperse their stocks of ammunition from central storage sites, making it more difficult to attack but at the same time making it less accessible to the Iraqi units deployed in Kuwait and southern Iraq.

The latest Israeli assessments on the progress of the allied offensive were made available in interviews at a time when Israeli officials are trying to encourage the United States to begin a ground offensive against Iraqi forces in Kuwait sooner rather than later.

Israeli officials are concerned that if the United States delays the start of the ground attack, the alliance it has built may wither for political reasons, or pressure will build for a negotiated settlement.

The Israeli comments came as Soviet and Turkish envoys met in Tehran with Iran's Foreign Minister Ali Akbar Velayati and others to discuss a new Iranian peace plan. Jordan's King Hussein also called today for a cease-fire.

The sources said the Israeli assessments, which differ considerably from some made public by U.S. and allied officials and contain more detail, are based in part on information from U.S. sources and in part on Israel's own intelligence sources. They would give no further details about what their assessments are based on.

U.S. military sources in Washington disputed similar Israeli assessments earlier this week, with one saying, "I have not heard any reports that positive."

Israel's first priority in the war is the destruction of the Iraqi military machine and the removal of President Saddam Hussein from power. In pursuit of that interest, officials in the government of Prime Minister Yitzhak Shamir have been arguing that the defeat of Iraq's army will be easier than many in the West believe.

One senior government official, speaking on the condition that he not be identified, said today that American officials might be withholding information on the damage to Iraqi forces in part because the Pentagon does not want to encourage expectations that a ground offensive is possible or advisable in the coming days.

"The American timetable for the ground attack is entirely military," the official said. "The problem is that for the Arabs, the timetable is political and psychological."

Washington's Arab allies, this official said, are eager to end the war as quickly as possible because of the risk that incipient popular opposition in their countries to the offensive against Iraq will grow out of control.

Israeli sources said several days ago that two Iraqi divisions had been involved in ground actions in southern Kuwait and Saudi Arabia last week and that 400 to 500 armored vehicles had been destroyed in what they described as "a severe defeat for Saddam."

Today, the Israelis said Iraqi tank losses had mounted to about 600, out of some 4,000 tanks Iraq is believed to have deployed in Kuwait and southern Iraq.

The Israeli officials said their reports showed that one of the eight Republican Guard divisions deployed near the Iraqi-Kuwaiti border had been hit hard in relentless raids by U.S. B-52 bombers and other aircraft.

By Israeli count, the Republican Guard division had lost more than half its tanks and armored vehicles. However, official sources suggested the heavy damage was an exception among the overall Republican Guard force, which is reported to be well dug-in.

U.S. officials have shown reluctance to discuss extent of allied damage to the Republican Guard, saying only that "there has been damage done" but that it is "difficult to quantify" and that any such reports could benefit Iraq.

Gen. Michel Roquejeoffre, the commander of French forces in the Persian Gulf, speaking at a briefing in Riyadh, Saudi Arabia, today, said, in one of the most optimistic assessments by an allied official, that the Guard "has been diminished by around at least 30 percent," the Associated Press reported.