FREETOWN, Sierra Leone (AP) _ With all but a small force of British troops leaving Sierra Leone Thursday, the former colonial power tried to allay fears that it was abandoning the war-ravaged country.

Britain has gradually withdrawn its 1,000-strong force, sent in May to stabilize the situation after rebels kidnapped some 500 U.N. peacekeepers. As they departed, the British handed over the defense of the capital and airport to a the U.N. forces.

``We are not leaving,'' British Deputy Prime Minister John Prescott said Thursday after meeting with President Ahmed Tejan Kabbah. ``We are going to be involved in the long-term, to work with other friendly countries to help maintain democracy in Sierra Leone.''

Only about 200 British military advisers are staying behind to help equip and train a new national army. The government is currently defended by an uneasy alliance of private militias and army soldiers, some of whom fought on opposing sides during eight years of brutal civil war.

Kabbah said he was confident the British departure would not leave a security vacuum in the West African nation, where the rebel Revolutionary United Front reignited the conflict in early May.

``The British forces were here to stabilize the security situation and that stability has been achieved and will be maintained,'' he said.

The outgoing British commander, Brig. David Richards, has said the U.N. mission has learned from its mistakes and no longer needs British support. The U.N. force has also nearly doubled in size, from about 6,000 to 11,850 troops.

Many Sierra Leoneans, however, have pleaded for the British forces to remain.

``This is a very sad day,'' said airport porter Foday Mansaray. ``The deputy prime minister is here, but the soldiers who are protecting us are going. What are (they) going to do if the rebels attack again?''

The rebels killed tens of thousands of civilians and systematically maimed many more in a campaign of terror.

Despite signing a July peace accord, the rebels began advancing on the capital, Freetown last month after seizing the U.N. hostages.

The captives have since been released, and the ragtag coalition of pro-government forces has been pushing the RUF away from Freetown. But more than 200 U.N. troops remain surrounded in rebel-held eastern Sierra Leone, where a new group of 21 peacekeepers has been detained.

As Prescott arrived Thursday morning, U.N. peacekeepers from Nigeria were attacked by RUF rebels in the western town of Port Loko, U.N. spokesman Fred Eckhard said in New York. There was a 45-minute exchange of gunfire before the RUF retreated into the bush. No casualties were reported.

Prescott visited the Royal Navy's HMS Ocean off the coast of Sierra Leone, which was headed back to Britain with the last of the withdrawing forces Thursday night.

He also toured the government base at Benguema, about 25 miles east of Freetown, where 45 British instructors will put 1,000 Sierra Leonean recruits through a six-week training course. About 150 other British troops will provide security.

Prescott was leaving Thursday night for Lagos, Nigeria, before returning to Britain.

Also Thursday, a committee of West African leaders began negotiations in Freetown for a new cease-fire.

The team is headed by Nigerian Maj. Gen. Gabriel Kpamber, the former commander of a West African intervention force that defended the government during the war. Also represented are Mali, Liberia, Ghana, Togo and Guinea.