It is expected to remain in place for up to six months as the authorities attempt to deal with unrest across the country.
Prime Minister Hailemariam Desalegn announced his surprise resignation in a televised speech on Thursday.
It was the first time in modern Ethiopian history that a sitting prime minister had quit.
He said he wanted to smooth the way for reforms.
It has also closed down a jail where activists alleged torture took place.
Many of the prisoners took part in anti-government protests in 2015 and 2016 in the country’s two most populous provinces, whose ethnic Oromo and Amharic communities complained that they are under-represented in the country’s corridors of power.
The demonstrations began against a government plan to expand the capital, Addis Ababa, but later developed into greater demands for civil rights.
The government previously imposed a state of emergency in October 2016, which was lifted in August last year.
During that time, curfews were in place, there were restrictions on movement and around 29,000 people were detained.
Amid the latest outbreaks of violence the government has banned protests as well as publications “that could incite and sow discord”.
Further emergency measures are expected to be announced later today.
Source: RTE News