Tension between United States and Israeli officials over the slowdown in resolving the Lebanese crisis is being matched on the ground by what are being interpreted as ''challenges'' to the US Marines by Israeli forces, according to sources close to the multinational peacekeeping force.
A series of confrontations over the past three weeks led to private communications from the US to Israel to cease attempts to cross into marine-controlled territory around Beirut airport.
But the appeal not to provoke an issue was apparently ignored. A subsequent incident last week led both the State Department and the Pentagon to go public with complaints about ''irresponsible'' actions.
Last week, a 15-man Marine ''reaction force'' was ordered on full alert, deployed in firing positions, when a two-jeep Israeli patrol attempted twice to cross into the US zone.
One marine officer was actually ''nudged'' by an Israeli jeep, but he held firm until the patrol departed 10 minutes later. As a result, officers have ''reemphasized the rules of engagement'' and ''certain tactical considerations'' to all 1,200 marines who man a buffer zone between west Beirut and the Israelis.
The incidents began when an Israeli patrol broke through a barbed wire US boundary line. Troops claimed they had merely gotten lost, a reason first accepted as credible.
But the following day, two attempts were made to cross into the US area. One involved an Israeli colonel who demanded to speak to US Marines commander, Col. Tom Stokes. The requests were refused, and the officer was referred to diplomatic channels.
One source close to the multinational peacekeeping force has said that the actions were ''not compatible to the atmosphere of cooperative negotiations for a lasting peace'' in Lebanon.
The source went further, suggesting that the repeated moves appeared to be a reaction to US pressure and the ''kneel to no one attitude'' of the Begin government.
''While Israeli diplomats are making certain points at the table, the IDF (Israeli Defense Force) is doing the same thing on the ground. I do not believe this is a coincidence,'' the source said.
Although the Pentagon originally played down the confrontations as ''not a serious matter,'' Defense Secretary Caspar Weinberger said in a television interview Friday, ''We are worried about isolated incidents of that kind that could grow into something much more serious.''
That concern is genuine, in light of a brief firefight last month between Israeli and Lebanese forces that left two Lebanese dead and one Israeli injured. Local investigators feel the Lebanese soldier started the shoot-out, but diplomats said the Israelis were out of bounds and should not have been traveling on the east Beirut road.
An IDF spokesman was quoted Sunday in The Jerusalem Post as saying that at no time have Israeli forces entered marine territory, even though a number of times ''terrorists'' have fled to the marine area after committing acts of sabotage.
US sources vehemently deny that saboteurs have sought shelter in their zone.
Following a rocket attack Monday on a building in Khalde, near the site of Israeli-Lebanese negotiations, the Israeli command issued a statement saying the rocket had been fired from an area under the control of the marines. A spokesman said the marines did not detect any rockets being fired from the area.
The incidents underline the importance of the marines in the multinational force, say diplomats, since the Israelis have not heeded appeals for cooperation with peacekeeping forces, such as United Nations troops in southern Lebanon. During their four-year presence, the UN troops were never able to manage to achieve Israeli troop withdrawal.