UNITED NATIONS - Sierra Leone's rebels were holding an estimated 300 U.N. hostages Friday after seizing a contingent of troops along with its armored vehicles in another devastating blow to U.N. peacekeeping efforts in Africa.
Helicopter surveillance showed rebels manning some of the 13 armored personnel carriers - emblazoned with the U.N. logo on the side - that were commandeered over the past few days from the 208-man Zambian battalion, U.N. spokesman Fred Eckhard said.
Eckhard said he couldn't confirm if the rebels of the Revolutionary United Front were using the captured U.N. vehicles to head toward Freetown, the capital, or if they were remaining in the interior of the country where they were spotted.
The seizures capped a week of daily U.N. hostage-taking by RUF rebels, who were known during Sierra Leone's bloody civil war for their brutal attacks on civilians that left thousands dead and tens of thousands more with their arms and legs hacked off.
Four Kenyan U.N. peacekeepers are believed to have been killed in the clashes and 12 have been injured, Eckhard said. Six rebels were killed, RUF spokesman Eldred Collins said in Freetown.
Eckhard estimated that the total number of hostages stood Friday at around 300.
Among the first detained were six U.N. civilians - a four-man U.N. helicopter crew and two passengers - who were released Friday from Kailahun in the east. Liberian President Charles Taylor, a longtime ally of rebel leader Foday Sankoh, interceded with Sankoh to gain their release. Libyan leader Moammar Gadhafi has also promised to talk with rebel leader.
There was no discussion yet whether the United Nations would evacuate any of its 8,700-strong peacekeeping force or its civilian staff in Freetown. Negotiations were instead focused on sending in reinforcements and getting regional political leaders to pressure Sankoh to release the captives.
At least 90 non-essential international aid workers and family members were evacuated Friday afternoon and flown out in U.N. helicopters to the Guinean capital, Conakry.
The biggest fear among Freetown's war-weary residents was that the United Nations itself would withdraw.
Speaking in Freetown, U.N. spokesman Lt. Col. Jaswinder Sandhu said no pullout was planned, but acknowledged that the spate of clashes and hostage-taking had jeopardized the ''basic premise'' of peacekeeping.
''In this case, one of the major parties has backed out of the agreement and has gone and attacked that very peace force. The very basis of this mission is now in question,'' he said.
Secretary-General Kofi Annan has warned that this week's attacks could imperil U.N. peacekeeping on the continent in the same way that the West shied away from African intervention after 18 Americans were killed in a botched U.S. raid in Somalia in 1993.
Of greatest concern is the new U.N. observer mission for the Congo, where questions were raised about the deployment after clashes Friday between Rwandan and Ugandan troops.
U.S. Ambassador Richard Holbrooke, who was in the Congolese capital Kinshasa on Friday with a delegation of Security Council ambassadors, said ''the situation in Sierra Leone is a lot more serious than the one here.''
The U.N. mission for Sierra Leone was dispatched beginning in December to oversee the peace agreement that ended a brutal eight-year civil war that left the country in ruins.
A power-sharing peace agreement was reached last July between the government and the RUF, but this week's fighting has threatened that shaky peace.
The RUF claims the clashes began because peacekeepers were forcibly disarming RUF fighters - a charge U.N. officials deny.
Eckhard said the bulk of the estimated 300 hostages came from the Zambian contingent that was disarmed and detained en route Wednesday and Thursday from the coastal town of Lungi to the central town of Makeni to reinforce peacekeepers who had come under attack there earlier in the week.
In addition, 100 or more Nigerians were detained in Kambia, in the northwest, then released without their weapons or uniforms in Port Loko to the south, U.N. officials said.
Eckhard stressed that the U.N. troops had a mandate to use deadly force to protect themselves and civilians in imminent danger - but that any decision on that would be made by the force commander.
''The emphasis is not to go to war with the RUF,'' he told a news conference.
Annan has called for a rapid-reaction force to move into Sierra Leone to reinforce the U.N. mission.
The United States, Britain and France have been approached but have not offered any ground troops. Britain has agreed to provide a technical support team to help with logistics planning in Freetown, the British Foreign Office said. Washington was studying a formal U.N. request for air transport, U.S. officials said.
The RUF, meanwhile, denied it held any hostages and suggested instead that the U.N. troops may have gotten ''lost in the bush'' during fighting in Makeni and Magburaka, where the first clashes were reported Monday.
Sankoh ''has ordered his field commander ... to organize a search party for the missing U.N. peacekeepers,'' RUF spokesman Gibril Massaquoi said in Freetown.
Such contradictions are common with the RUF and Sankoh, an unpredictable and mercurial leader seen as a near-deity by many of his followers.
