By Guled Mohamed
MOGADISHU, June 28 (Reuters) - A roadside bomb killed two soldiers in Somalia's chaotic capital Mogadishu on Thursday, witnesses said, hours after two aid workers were shot dead in an overnight attack in the north of the country.
The incidents were the latest in an escalating wave of guerrilla strikes in the lawless Horn of Africa nation blamed on an ousted hardline Islamist movement.
One woman at the scene of Thursday's blast said a vehicle carrying troops through a northern district of the city was lifted into the air by the powerful explosion. The troops on another truck in the convoy opened fire, she said.
"I saw two dead soldiers," said another witness, Halimo Hussein, selling livestock feed at a nearby junction. It was not immediately clear if the dead troops were from the Somali interim government forces or their Ethiopian military allies.
Four civilians were also wounded in the explosion.
Separately, two Somalis working for U.S.-based International Medical Corps (IMC) relief agency were shot dead by unknown gunmen late on Wednesday in the central town of El-Berde.
In a statement from its California headquarters, the organisation identified them as Mohammed Muse Ali, a nurse supervising its activities in El-Berde, and Leyl Idiris, a contract rental car driver.
"Initial reports indicate the attack appeared to be related to tensions between rival clans living in the area," IMC said, adding that its work helped about 20,000 Somalis.
"International Medical Corps mourns the loss of both victims and condemns the violence that claimed their lives. We are deeply concerned about the deteriorating security environment in the area and urge the international community to address the situation with the highest degree of priority."
ETHIOPIA SLOWS WITHDRAWAL
Somalia's interim government -- the 14th attempt to set up central rule in Somalia since the 1991 fall of a military dictator -- is struggling to impose any sort of authority.
On Thursday, the U.N. refugee agency UNHCR said more than 3,500 people fled Mogadishu in June amid escalating violence.
Meanwhile, only 123,000 of an estimated 401,000 civilians who fled heavy fighting in the city between February and May have returned, it said in a statement. In another major displacement, it said, some 10,000 people have fled fighting between rival clans in and around the southern port of Kismayu.
In Ethiopia, Prime Minister Meles Zenawi said the activity of "terrorists" in Somalia -- whom he accused rival Eritrea of backing -- had forced him to revise his military exit strategy.
"Our defence forces had no option but to slow down their process of withdrawal which, if allowed to continue, would have led to a complete reversal of the victory achieved," he said.
Ethiopia's withdrawal now depended on the success of a planned national reconciliation conference, he told Ethiopia's parliament, the "consolidation" of the Somali government and the "full deployment" of African Union (AU) peacekeepers.
Only 1,600 Ugandan soldiers have gone to Mogadishu so far, though the AU wants to deploy an 8,000-strong force.
Meles told Reuters last month that Ethiopia has "more or less 4,000" soldiers in Somalia. But Somalis, and diplomats in the region, generally estimate a much higher number.
(Additional reporting by Tsegaye Tadesse in Addis Ababa, Andrew Cawthorne in Nairobi, and Ibrahim Mohamed in Mogadishu)
(For more information about emergency relief visit Reuters AlertNet http://www.alertnet.org email: alertnet@reuters.com; +44 207 542 5791)