Four opposition politicians in Ethiopia have been given six-month jail sentences for contempt of court after refusing to stand up or speak to the judges.

Last month, they received similar sentences for singing a protest song in court.

Among them is Bekele Gerba of the Oromo Federalist Congress, who has been in prison since 2016 after being accused of instigating protests.

Tens of thousands of people have been detained and held without trial for taking part in the demonstrations.

In a surprise move last month, the Ethiopian government said imprisoned opposition politicians would be pardoned.