PORT GENTIL, GABON, MAY 29 -- Government troops sent to quell widespread civil disorder in this coastal oil center clashed violently with bands of anti-government protesters today, leaving at least 15 people wounded by gunfire and grenade fragments, authorities said.

Witnesses said the troops, backed by armored cars, also used tear gas to disperse protests organized in support of the opposition Gabon Progress Party and arrested at least 20 people, including three party leaders.

Port Gentil, Gabon's oil processing and transshipment center 80 miles southeast of Libreville, the capital, had been in turmoil since last Wednesday, when Progress Party leader Joseph Rendjambe was found dead in a Libreville hotel room under suspicious circumstances.

His followers rioted in several cities and took control of much of Port Gentil, burning the French Consulate and taking some foreign oil executives hostage for several hours.

Foreign oil companies drastically cut production because of the turmoil, and France sent reinforcements to its former colony to protect French property and oil workers.

By the time Gabonese troops moved into the city this morning, French soldiers had gathered about 1,000 foreign oil workers into special centers where they could be protected or evacuated if necessary. Nearly all wives and children of the workers already had been evacuated.

Gabon earns 80 percent of its income from oil and would quickly run out of money without it, officials of President Omar Bongo's government said. In Paris, the state-owned oil company Elf-Aquitaine announced it would gradually resume production on its 60 offshore rigs, with output expected to reach 80 percent of the normal 101,000-barrel daily flow by Wednesday.