Addis Ababa often rejects rebel claims
* Rebels say troops tried to 'silence' U.N. witnesses
* Two U.N. workers still missing
By Aaron Maasho
ADDIS ABABA, May 16 (Reuters) - Ethiopian government troops have killed more than 100 civilians, including a local U.N. worker, during a five-day military operation in the oil and gas-rich Somali Region, a rebel group said on Monday.
More commonly known as the Ogaden, the ethnic Somali province is home to a low-key insurgency led by the Ogaden National Liberation Front (ONLF), which has fought for independence since 1984.
Government officials could not be reached for comment.
"The Ethiopian army and its local conscripts killed more than 100 civilian people from May 10 - 15 in the area, (and it) is still on going," the ONLF said in a statement.
"The (ONLF) intelligence service has ascertained that the Ethiopian army conducted the killing and abduction of U.N. local staff in the Ogaden jointly with the notorious militia of the (local) administration," it said.
The United Nations' World Food Programme (WFP) said on Saturday that one of its drivers had been killed in an ambush by unknown gunmen in an attack that left another staff member wounded. [ID:nLDE74D0CU]
Two members of the convoy were also missing, WFP said.
The ONLF said the incidents occurred while government troops conducted "kill-on-sight" operations in the Ogaden's Fafan valley and that the attack on the U.N. convoy was an attempt to "silence" its employees who had witnessed the operations.
Authorities in Addis Ababa were not immediately available for comment, but they usually reject the group's claims as "baseless propaganda".
The allegations are impossible to verify because journalists and aid groups cannot move unhindered in the area.
This is not the first time the ONLF has accused government troops of atrocities in the region. The group said in January that soldiers had arbitrarily executed civilians and carried out ethnic cleansing in the province, a charge dismissed by the authorities. [ID:nLDE70K10N]
Ethiopian forces waged an offensive against the rebels in late 2007 after the ONLF staged a pre-dawn attack on a Chinese-run oil facility, killing 74 people. Analysts say the rebels have since been weakened, but are still capable of launching hit-and-run attacks.
Ethiopia signed a peace deal in October with one faction of the ONLF, though another wing labelled the deal "irrelevant". The faction with which Addis Ababa sealed the accord says it represents 80 percent of the group's fighters.
The Horn of Africa nation says the Ogaden basin may contain gas reserves of 4 trillion cubic feet and major oil deposits. (Editing by Richard Lough and Elizabeth Fullerton)