Libya's Muammar Qaddafi, suddenly escalating a forgotten little African war, has dispatched columns of reinforcements and Soviet-built bombers to strengthen his troops fighting on one side of a bloody struggle for power in neighboring Chad, news service and diplomatic reports said yesterday.

The influx of additional Libyan troops and bombing runs by Libyan warplanes brought Qaddafi's commitment in the long Chadian conflict to a new high and gave at least temporary advantage to the forces of President Goukouni Oueddei, son of a northern Moslem religious ruler with sympathy for the pan-islamic Qaddafi government.

It underlined the extent of Libyan involvement in the 16-year-old civil war that, in one form or another, has kept the destitute people of Chad embroiled in battle since their independence from France in 1960 and has divided the central African country -- reportedly the site of promising uranium deposits -- into a patchwork of rival guerrilla fiefdoms.

Qaddafi has for years offered support to one Chadian guerrilla group or another, sometimes two opposing bands at the same time, in an effort to get a government sympathetic to his brand of Islamic nationalism. Five years ago, he announced annexation of a barren strip of the Tibesti Desert along the border that had been taken over by his soldiers.

Goukouni, at a news conference on Libyan soil broadcast by Libyan radio, hinted yesterday that the recent Libyan buildup is aimed at permitting him to gain a decisive victory over his opponents after months of indecisive bloodletting.

He paid tribute to Libya for "the uninterrupted and unlimited assistance" provided by Qaddafi and said the confused situation in Chad will soon be settled "to the profit of the legal government."

Goukouni's main opponent in the current fighting is former defense minister Hissene Habre, a Western-oriented law graduate from the University of Montpellier in France whose irregulars at last report controlled the southern sector of the capital, Ndjamena, and a fan-shaped swath of territory running north and east toward the northern city of Faya Largeau.

Reports from the neighboring country of Cameroon said some of the new libyan troops last week took over Faya Largeau on behalf of Goukouni while another unit moved into Ndjamena to strengthen Goukouni's hold over the northern sector of the divided capital.

Diplomats in Douala, Cameroon, told United Press International that the Libyan troops apparently were airlifted into Chad from bases on the 60-mile-wide Aouzou Strip, the Chadian territory occupied by Qaddafi in 1973 and annexed two years later on the strength of a 1935 treaty between France and Mussolini's Italy.

A spokesman for Habre said in Paris that "large numbers" of Libyan troops with heavy equipment have been seen arriving in convoys in Ndjamena in recent days to back Goukouni, Reuter reported. Ahmad Allah Mi, a former charge d'affaires at the Chadian Embassy in Paris, added that about 350 Libyan regulars have been in the Chadian capital for some time and that 20 have been captured by Habre's forces.

He denied the reported capture of Faya Largeau, however, and disputed a claim by the official Libyan news agency, Jana, that Qaddafi visited the crossroads town in person Tuesday along with Goukouni to celebrate the "decisive victory against the mercenary forces of rebel Hissene Habre."

"I would be very surprised if he went to Faya because the town is still in our hands," Allah Mi told Reuter.

The Habre aide acknowledged, however, that Faya Largeau had been bombed by Libya's Soviet-made TU22 warplanes, the same craft that he said bombed Habre positions in Ndjamena four times in October.

There was no way to resolve the conflicting claims. Most information from Chad has been second-hand since Habre and Goukouni fell out last March, disbanded the government to which they both belonged and resumed the warfare that had been calmed by an agreement in Lagos, Nigeria, only months before.

The fighting in late March and early April left approximately 800 persons dead. Largely because of the uncontrolled combat, the United States shut its embassy in Ndjamena and evacuated all U.S. diplomats. By May, France pulled out its remaining troops, ending years of military involvement in its troubled former colony and apparently despairing of restoring order among the competing armed factions.

French support traditionally had gone to the Christian and tribal southern Chadian groups who ruled from independence until last year's Lagos accord. That agreement set up a provisional government under Goukouni designed to share power among the dozen armed groups that were left over from a decade of civil war between the French-backed southerners and the mostly Moslem northerners backed by Qaddafi.

Qaddafi's motives in Chad remain obscure. There are widespread reports that the country's northern stretches contain uranium deposits. These reports are based mostly on the fact that neighboring Niger has workable deposits, however, and Chad itself has not been explored enough to determine whether it also has uranium, informed U.S. sources said.

The libyan leader more likely is seeking to guarantee a government sympathetic to his aims for some form of union among Saharan-area Moslem states, observers said. Habre, although also a Moslem who fought against the French-backed southerners, is considered to be more attuned to the West and more likely to set up a government along traditional lines than Goukouni.