JERUSALEM (AP) _ Israel's chief of staff expressed concern Sunday that the Bush administration 's proposed multibillion-dollar weapons sales to Saudi Arabia could destabilize the military balance in the Middle East.

Chief of Staff Lt. Gen. Dan Shomron also said Israel was worried about events in neighboring Jordan, especially the recent visit of radical Palestinian guerrilla leaders George Habash and Nayef Hawatmeh.

The Bush administration reportedly is preparing to submit to Congress a request to sell Saudi Arabia at least $18 billion worth of weapons, including F-15 fighter planes, helicopters, tanks and other sophisticated arms to bolster the desert kingdom's defenses against Iraq.

The administration has already proposed selling Saudi Arabia $3 billion in new weapons, including F-15s, M-60 tanks, 15,000 rounds of armor-piercing anti-tank ammunition and 200 Stinger anti-aircraft missiles.

Speaking on Israel radio, Shomron said the arms deal would give the Saudis ''a large quantity of weapons, which are also of the highest quality.''

''From our point of view, giving such weapons ... to countries that are still formally at war with us is certainly not a recipe for stability,'' Shomron said.

''I hope this situation will be balanced in order to guarantee in the future our technological superiority and deterrent capability,'' he said.

According to Israeli sources, Defense Minister Moshe Arens, who is now in the United States, plans to ask Washington for money to help Israel's defense industry develop weaponry, as well as for U.S.-made weaponry such as F-15 and F-16 fighter planes.

Turning to the gulf crisis, Shomron predicted that Iraq might be able to withstand the lack of food and other goods caused by the U.N. trade embargo but not a shortage of spare parts for the army.

''It is easier to convince people that for the cause of a just, important war they should be content with less food or services,'' Shomron said.

''If this problem of spare parts for weapons systems, mostly advanced systems, does not exist today, it will soon become a serious issue.''

Shomron said Israel was concerned about developments in Jordan because of its strong support for Iraq and the reappearance of radical Palestinian leaders in the kingdom.

Habash and Hawatmeh have been supported by Syria but are now reportedly moving their headquarters to Iraq.

''Securing the border between us and Jordan is mostly under the responsibility of the Jordanian army, and there are many Palestinians in it too,'' Shomron noted. ''This situation carries many dangers; we are watching and we are alert to any possibility of a change.''

He reiterated Israel's long-standing policy that the entrance of Iraqi forces into Jordan would trigger a military response from Israel but qualified it, saying: ''I propose to remember ... that this is subject to consideration, to carefully determining what has entered, and for what purpose, but in principle this is a red line.''

''We are preparing our forces for every eventuality, from the point of view of training, weapons and logistics,'' Shomron said.