WASHINGTON: The United States said Saturday it was "deeply concerned" by the conviction and sentencing of Ethiopian journalist Eskinder Nega, who was jailed for 18 years on "terrorism" charges.

"The United States remains deeply concerned about the trial, conviction, and sentencing of Ethiopian journalist Eskinder Nega, as well as seven political opposition figures, under the country's Anti-Terrorism Proclamation," State Department spokeswoman Victoria Nuland said in a statement.

She said that the Ethiopian government had used the Anti-Terrorism Proclamation to jail journalists and opposition party members for peacefully exercising their freedoms of expression and association.

"This practice raises serious concerns about the extent to which Ethiopians can rely upon their constitutionally guaranteed rights to afford the protection that is a fundamental element of a democratic society," the statement said.

"We reiterate our call for the Government of Ethiopia to stop stifling freedom of expression and we urge the release of those who have been imprisoned for exercising their human rights and fundamental freedoms," Nuland pointed out.

Nga and 23 other reporters and activists received between eight years and life in prison.

They had been accused of promoting anti-government protest in Ethiopia, including by using examples of the Arab Spring uprisings in the media.

All of the defendants were convicted under Ethiopia's anti-terrorism law, which rights groups criticise for being vague and helping quash freedom of speech and peaceful political dissent.