A prison in Ethiopia where high-profile politicians are held has caught fire and gunshots were later heard there, according to media and opposition activists in a country gripped by a wave of protests.

The jail, Qilinti, is on the outskirts of the capital Addis Ababa and is used to imprison leaders of the Oromo ethnic group, among others. Members of the Oromo community have been leading demonstrations against the government since November, demanding more political and economic freedoms.

Fortune, a privately-owned newspaper, reported that there had been 20 casualties, but did not specify whether it meant dead or wounded. It carried a photograph of a huge plume of smoke billowing over a row of buildings, and said the fire had been brought under control by Saturday evening.

The paper said that three firefighters had been taken to hospital with breathing difficulties.

A pro-government radio station reported that one person had been killed, and six injured. Opposition activists put the number of dead at between 20 and more than 30, citing family members of inmates.

Al Jazeera could not independently verify the reports.

Fortune, citing sources, reported that the fire had been deliberately started as part of an escape attempt and said that police had now taken control of the facility from prison officers.