Israel and Lebanon resumed their military negotiations here today, and Israeli officials said there were signs of progress toward an agreement on how the planned Israeli withdrawal from the Sidon area will be handled.

The two military delegations met at the United Nations southern Lebanon headquarters in this border town. The two sides still appeared to be far apart, but after more than four hours of meetings they agreed to return here on Thursday. The Lebanese promised to come with a detailed response to Israel's plans to begin a staged withdrawal from southern Lebanon.

"Yes, definitely there is progress," said Lt. Col. Yona Gazit, a spokesman for the Israeli delegation, after the meeting.

"It is mainly in the fact that on Thursday we will continue discussing the coordination of an orderly transfer of the Sidon area from Israel to the Lebanese Army and, we hope, to U.N. forces."

The talks here today were the first meeting between the two sides since the Israeli Cabinet approved the first stage of a three-part withdrawal plan last week that Israel hopes will see its troops largely out of Lebanon by next fall. The Cabinet's tentative adoption of the unilateral withdrawal plan, whose second and third stages will require further votes, came after two months of negotiations failed to produce agreement on security guarantees that Israel was seeking as a condition of its withdrawal.

The first stage of the withdrawal, from the port city of Sidon and the surrounding area, is scheduled to be completed by Feb. 18. The key issue now in the resumed negotiations is whether there will be any organized military force able and willing to take control of the evacuated area as the Israelis leave.

Lebanon has said its Army can handle the task, but Israel also is seeking a redeployment of the U.N. force that is stationed in southern Lebanon north to the Sidon area to handle security there. That, however, would require approval by the U.N. Security Council, preceded by a formal request for U.N. help from Lebanon, a request that the Lebanese so far have not been willing to make.

At today's meeting, the Israeli delegation explained the withdrawal decision and, according to an official communique, the Lebanese delegation "expressed its reservations."

Brig. Gen. Mohammed Haj, the head of the Lebanese delegation, was quoted as saying the planned Israeli withdrawal was not a real pullout from Lebanon but the "redeployment" of Israeli forces. Haj said that Lebanon was demanding a "firm timetable" for the withdrawal accompanied by detailed maps of the Israeli plans.

But sources here also quoted Haj as suggesting during the meeting that Lebanon might be willing to have U.N. troops enter Sidon under certain conditions. He was quoted as specifying that the U.N. force not be used "as an internal buffer to divide Lebanon or as a cover for Israeli occupation."

Haj also called for the implementation of a six-year-old U.N. resolution calling for the U.N. force to be deployed along the Israeli-Lebanese border, a step the Israelis have never allowed, the sources said.