Fighting in Chad between government forces and Libyan-backed rebels is settling down into what U.S. officials say they believe will be a long and inconclusive stalemate. The U.S. officials say they do not believe Libyan leader Muammar Qaddafi will withdraw his troops from the central African country in the foreseeable future.

Senior officials here say that the government of President Hissene Habre therefore will require U.S. aid for some time to come, in addition to $25 million already drawn from an emergency fund under the Foreign Assistance Act.

There are no outstanding Chadian requests for American help, the officials say, but the administration now sees the Chadian problem as a long-range one, and is drawing up a strategy and objectives paper setting out how to deal with it accordingly.

"Qaddafi is going to try and maintain his influence in Chad for as long as Qaddafi is in Tripoli," one official said. "This is a long-term problem, and with the means at his disposal the Chad government is going to need additional help to resist him."

About half the $25 million allocated to Chad has already been spent on antiaircraft missiles, vehicles, spare parts, ammunition and other supplies for the Chad army. Last weekend, Pentagon officials said, a used Air Force C130 Hercules transport was handed over to the Chadians in the capital, Ndjamena.

Since the strategic northern desert outpost of Faya Largeau fell to the Libyans and rebels under former president Goukouni Oueddei on Aug. 10, U.S. officials said, the Libyans have continued to build up their forces in the northern half of Chad under their control.

U.S. intelligence reports show a total of 3,500 to 4,000 Libyan regulars inside Chad with up to 100 tanks, armored personnel carriers and armored vehicles.

Up to 30 light reconnaissance and ground attack aircraft, as well as a number of Soviet-made Hind helicopter gunships, are dispersed around three or four desert airstrips, the largest at Faya Largeau. There are also some supersonic fighter planes based in the Aouzou area on the Libyan-Chadian border.

The Libyans, under the command of a senior army officer, have established their operational headquarters at Ounianga Kebir, northeast of Faya Largeau, from where they coordinate with the rebel forces.

But despite this buildup, officials say, the United States does not expect Qaddafi to venture beyond the line, roughly along the 15th parallel, that the French have set as a limit to southward expansion by the Libyans and Goukouni.

"They are digging in, improving their defenses, building up their equipment and numbers, but there is no indication that they're going to try and penetrate further south," said one State Department official.

The U.S. analysis is that the stalemate will continue as long as both the Chadian government and rebels fail to draw their allies, France and Libya, respectively, deeper into the conflict.

France, at the urging of the United States, last month sent 2,000 troops to Chad, but has declined to sponsor a government counteroffensive against the Libyans and Goukouni's forces.

"The French are not prepared to go north and the Libyans are not prepared to go south," the State Department official said. "Each of the Chadian sides realizes that its military objectives can only be realized with the assistance of its partner," he added. "Neither is satisfied with the current stalemate."

Officials here are reluctant to revive the embarrassing row that broke out last month over apparent differences of approach to the crisis between the Reagan administration and the socialist government of President Francois Mitterrand, but insist that the French must "take the lead" in Chad.

The United States sent two airborne warning and control system (AWACS) planes to neighboring Sudan, but withdrew them after the French failed to deploy fighter aircraft to deter Libyan bombing raids.

"There was a great deal of consultation between us and the French, but we would now like to see that dispute laid to rest," one official said.

Officials say the intelligence reports indicate that the Libyans are experiencing difficulties with over-extended supply lines, poor communications, the harsh climate and the almost total lack of infrastructure in the area under their control. But they say they do not underestimate Qaddafi's ability to continue to make trouble in Chad.

"His behavior is sometimes bizarre but he is certainly capable of formulating sophisticated strategies and reformulating them as events require," said one.

"Qaddafi," said another official, "does outrageous things, but they are calculated. Sometimes he retreats, that's true, but sometimes he goes forward. Unless you appreciate what his goals are he might look irrational. I think the worst thing you can do is to think he's crazy."

U.S. analysts and officials concede that Qaddafi has won at least a partial victory in Chad, and say that diplomatic efforts must now concentrate on using the United Nations and the Organization of African Unity to persuade the Libyans to back down.

"Qaddafi," said an administration official, "is not very talented, and he has been inept. But if he keeps going he's going to succeed somewhere. He does keep trying."