A three-judge panel found all 16 defendants guilty of conspiracy to wage war on Ethiopia's government as part of a plan to establish a separate Oromo state.
The sentences were handed down last week, but the news was delayed due to the Easter holidays.
The defendants were arrested in 2007 and 2008, accused of being members and sympathizers of the Oromo Liberation Front, which the government considers a terrorist group. Most received jail terms of 10 to 13 years without parole. But alleged group leader Mesfin Abebe was sentenced to death, and another defendant, Tesfahun Chemeda was given a life term.
Justice Ministry spokesman Mekonnen Bezabeih said the charges included killings and armed robberies aimed at terrorizing the population and financing the OLF's separatist campaign.
“They were high officials of the OLF party and they tried to overthrow the government and tried to secede the Oromia federation from the federal states,” the spokesman said, “and they robbed a factory, they killed police and other security persons in Oromia.
The accused included several prominent Oromo businessmen and politicians. Two were well-known Addis Ababa hotel operators. Another was Bekele Jirata, general secretary of the Oromo Federal Democratic Movement, which is part of the main opposition bloc in Ethiopia's upcoming elections for parliament.
Bekele has been listed in the U.S. State Department human rights report as a political prisoner, and other defendants in the case are listed as victims of arbitrary detention.
But Bekele had been released on bail during the court proceedings, and disappeared early this year. He was sentenced in absentia.
OFDM party leader Bulcha Demeksa said Bekele had denied being an OLF member, and had fled the country to escape what he thought would be an unfair verdict.
“He knew that they never care for evidence, they just sentence you to whatever they want,” Bulcha said.“He knows that, so he had to run away.
Bulcha said Bekele had alleged that he had been tortured in prison, charges the government strongly denies.
The OLF case is the second in recent months in which death sentences were handed out to alleged coup plotters. Five prominent opposition political activists were sentenced to die in late December in the so-called Ginbot Seven, or May 15th, case.
Four of those, including Ginbot Seven party leader Berhanu Nega, were sentenced in absentia. Berhanu, who was elected mayor of Addis Ababa in Ethiopia's May, 2005 elections, never took office and currently lives in exile in the United States.
The only Ginbot Seven defendant present in court to hear the death sentence pronounced was Melaku Tefera, an official of the opposition Unity for Democracy and Justice party. UDJ leader Birtukan Mideksa is also in jail, serving a life sentence in connection with violent post-election demonstrations in 2005.