The forces were believed to be members of the Oromo Liberation Front, an Ethiopian rebel group opposed to the government of Ethiopian Prime Minister Meles Zenawi. Eritrea, which is at war with Ethiopia, is allied with Aidid and also is backing the Ethiopian rebels.

The war between the two Horn of Africa nations spilled over into Somalia earlier this year when Eritrea sent at least three shipments of arms and Oromo fighters to Aidid.

Ethiopia has since captured several towns held by Aidid or his allies in the western part of southern Somalia.

Residents contacted by VHF radio Saturday said a large and heavily armed convoy of close to 500 Oromos passed through the towns on their way from the port town of Fah, 500 kilometers (310 miles) north of Mogadishu to Aidid's stronghold at Baligdoglie, 90 kilometers (60 miles) south of the capital. They residents spoke on condition of anonymity.

Witnesses said militiamen in the towns in between, which are controlled by pro-Ethiopian factions, were too frightened by the superior equipment of the Oromos to put up any resistance.

The move overnight Friday followed the drive-by killing Thursday of an Islamic fundamentalist commander in the capital Mogadishu.

Relatives said the family and officials of his Al-Itihad Al Islamia group suspected Ethiopian agents assassinated the commander, who in the past seven years organized raids to eastern Ethiopia's Ogaden region, which Al-Itihad wants joined with Somalia.

Aidid officials have denied reports he is allied with the Al-Itihad.

Meanwhile, in southern Mogadishu, about 300 militiamen of the Islamic courts conducted a widespread cleanup operation at four key junctions Saturday around the city's main Bakara market. An exchange of fire took place and at least one gunman was killed before the court forces arrested 11 others suspected of extorting money from merchants.

The courts, backed by businessmen in the area, are sponsoring an ad-hoc police force in the lawless city to fight crime.

Colonel Abdullahi Irad of the Al-Ittihad group was shot dead late on Thursday by four gunmen who fired from a taxi outside a mosque in an area of south Mogadishu controlled by warlord Hussein Aideed.

Witnesses said the assailants shouted Irad's name before firing at his upper chest as he tried to flee to the safety of the mosque.

Irad was head of operations for Al-Ittihad. For the past seven years he had organised hit-and-run attacks into Ethiopia with the aim of liberating Zone Five -- a region inhabited mainly by ethnic Somalis -- from Ethiopian rule.

After his funeral on Friday, relatives of Irad said he had been assassinated by Somali gunmen manipulated by Ethiopia.

Ethiopia has deployed an estimated 3,000 troops in Somalia in recent months to battle its enemies, including Al-Ittihad and an Ethiopian rebel group, the Oromo Liberation Front, which operates from bases in Somalia.

Both groups are supported by Aideed, whose faction is armed by Eritrea -- Ethiopia's enemy in a year-long border war.

Gaddafi, who is trying to bring warring Ethiopia and Eritrea together, will be participating in an OAU summit for the first time since 1977.

He will be staying in downtown Algiers as a guest of the Algerian government before moving to his tent, pitched near the summit venue outside the Algerian capital, officials said.

``Gaddafi is now the guest of the government and will stay in his tent afterwards, as he refuses to stay in the Sheraton hotel which he says is a sample of American imperialism,'' an official said.

The official could not say exactly when Gaddafi would move to his tent -- one of his trademarks when travelling abroad, along with his army of female bodyguards.

African leaders will stay at and gather in the newly built Sheraton hotel for the three-day OAU summit, the final one of the century, at the Club des Pins coastal area some 20 km (12 miles) outside the Algerian capital.

The United States broke off relations with Tripoli in 1981, charging that the Libyan government was supporting terrorism. Britain did so three years later after the shooting of a policewoman near the Libyan embassy in London.

Britain resumed diplomatic relations with Libya on Wednesday but Washington says it is too soon to restore formal ties.

On Friday, the U.N. Security Council complimented the Libyan government for its cooperation in the investigation of the bombing of an American airliner in 1988 above the Scottish town of Lockerbie, and promised to lift U.N. sanctions as soon as possible.

The embargoes, first imposed in 1992 and tightened two years later, include an air and arms ban as well as a freeze on some financial assets. They were suspended on April 5 when Tripoli handed over the two men suspected in the Lockerbie bombing.

The United States insists that it cannot lift the sanctions until the trial of the two suspects, before a Scottish court in the Netherlands, had begun.