President Reagan is committed to keeping U.S. Marines in Lebanon as part of the multinational peace-keeping force there and sees no imminent danger in doing so, the White House said yesterday.

In response to a report that U.S. military officials are concerned that Marines there could become involved in fighting, deputy press secretary Larry Speakes said no U.S. military officials have indicated to Reagan any increased likelihood that such fighting may break out.

Military leaders said Friday that they fear the Marines' extended stay in Lebanon, now approaching five months, adds to the chances of incidents that could accidentally touch off military action.

The Marines entered Lebanon for the second time last year on Sept. 28, and 1,200 are now stationed on the ground there, with another 600 on five ships offshore. Administration officials had predicted that the Marines would be out of Lebanon by the end of 1982.

Marine officials are considering placing all of the U.S. troops aboard ships to get them out of heavily armed Lebanon.

"We recognize that it is a situation that is not completely free of danger," Speakes said. "But then again, it is not fraught with danger."

"We don't anticipate any major conflict involving U.S. Marines because they have been there for however long, three to four months, without any major incident," Speakes said. "And they are in a situation where they are not in conflict, not in contact with anybody that could produce a major incident."

A Pentagon official said planning is under way on how best to increase the U.S. presence in Lebanon by one battalion if Reagan agrees to a request by Lebanese President Amin Gemayel for additional U.S. troops.

Speakes said he had no comment about additional U.S. forces entering Lebanon but said Reagan remains convinced of the need to keep the current Marine force there.

"It is our desire that the Israeli-Lebanese troop withdrawal talks move forward and that the foreign forces can be removed and that the U.S. presence can be removed," Speakes said. "But it is our desire, too, that they stay there as long as necessary to ensure stability in the Lebanese government."

Last week, Israel and Lebanon agreed on an agenda for negotiating terms of the withdrawal of Israeli troops from Lebanon. In return for withdrawal, Israel is asking that Lebanon agree to establishment of a "security zone" in southern Lebanon to prevent military action against northern Israeli towns.

Lebanon is occupied by Israeli, Palestinian and Syrian troops in addition to the multinational force from the United States, Italy and France. U.S. Marines now in Lebanon are scheduled to be replaced by a new group in mid-February.