Reports from Eritrea say a group of soldiers have surrounded the ministry of information building in the capital, Asmara.
State TV has also reportedly been taken off air in what some have described as a coup attempt.
The city is said to be calm with no shots having been fired.
Eritrea’s government has been criticised by human rights activists as one of the world’s most repressive and closed countries.
The websites of key Eritrean state and ruling party media are currently operating erratically, with the site for the ruling People’s Front for Democracy and Justice (PFDJ) party inaccessible.
A statement has reportedly been read out on state radio and television calling for the implementation of the country’s 1997 constitution.
The UK Foreign Office said that it had received reports of “unusual military movements in and around Asmara”, and noted that local radio and TV appear to have been shut down.
President Isaias Afewerki has ruled the country as a one-party state since independence from neighbouring Ethiopia in 1993.