FREETOWN, Sierra Leone (CNN) -- Armed forces backing Sierra Leone's beleaguered government were gearing up Sunday to launch a counterattack against rebels who had overrun part of the country's capital earlier in the week.

Witnesses said reinforcements for the Nigerian-led West African coalition force (ECOMOG) arrived overnight at the Lungi International Airport, where the force has its main base.

"We are pushing the rebels further east," a senior ECOMOG officer said late Saturday. "We are going to continue until the operation is complete."

Rebel troops swept into Freetown's Eastland district on Wednesday, catching government and ECOMOG troops by surprise. But on Saturday, Nigerian warplanes took off from Lungi airport to pound rebel positions.

The rebels have demanded that President Ahmad Tejan Kabbah, elected in 1996, step down, and that the government release rebel leader Foday Sankoh from jail. Sankoh has been sentenced to death for treason for his role in organizing the rebel Revolutionary United Front.

RUF guerrillas have waged war against the Sierra Leonean government for years. Countless civilians have been killed or injured in the battles.

Mediation efforts under way

Kabbah and Sankoh jointly called for a cease-fire on Thursday, but RUF military commander Sam Bockarie refused to abide by it until he was allowed to meet with Sankoh face-to-face. Instead, Bockarie intensified his efforts in Freetown.

The government appeared to be working toward arranging a meeting between Bockarie and Sankoh. But Bockarie warned that he would not leave his stronghold for a meeting with his leader or with international mediators who are trying to broker a cease-fire.

"Why should I leave my ground?" he told Reuters by telephone. "I am not going to accept that. There is a trap."

Meanwhile, regional efforts to broker a cease-fire got under way Sunday. Ivory Coast Foreign Minister Amara Essy and his Togolese counterpart Joseph Kokou Koffigoh traveled Guinea to meet with President Lansana Conte and were planning to fly to Lungi airport on Monday.

"The Sierra Leoneans have asked me to come," Essy said Saturday. "Both President Kabbah and the leaders of the Revolutionary United Front have asked me."

Ivory Coast brokered a short-lived truce in 1996. Kabbah was deposed by a military coup in 1997 and reinstalled as president just 10 months ago by ECOMOG.

Reuters contributed to this report.