The government previously imposed a state of emergency in October 2016, which was lifted in August 2017.
Citing a decision by the council of ministers, the the Ethiopian Broadcasting Corporation (EBC) said: "A state of emergency has been declared as of now".
"We strongly disagree with the Ethiopian government's decision to impose a state of emergency that includes restrictions on fundamental rights such as assembly and expression, " the statement said.
He also ruled out a transitional government. Siraj says security forces are instructed to take "measures" against those disturbing the country's functioning.
Numerous 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.
In January Desalegn announced all political prisoners in the country will be released and Maekelawi, a prison ward at the center of torture allegations, will be closed.
Poor show in CHAN affects Uganda latest Federation Internationale de Football Association ranking
Nigeria's Super Eagles have further crashed in February ranking released by the World football governing body, FIFA, on Thursday. Congo DR climbed four places to attain the 39th position, while Egypt , defending Nations Cup winners slipped 13 places to 43rd.
Ethiopian Prime Minister Hailemariam Desalegn resigned unexpectedly on Thursday, the first leader to do so in the country's recent history.
Rights groups claimed people were beaten and subjected to arbitrary detentions under the previous emergency rule. The government said those arrested by mistake were released and those who unwillingly took part in the unrest were released after what it described as "trainings".
Initially, there there was a "strong push" against the decision from members of two of the parties that make up the EPRDF: the Oromo Peoples' Democratic Organization (OPDO) and the Amhara National Democratic Movement (ANDM), the two parties that govern Oromia and Amhara regional states, according to our source.
The United States is now warning its embassy personnel to suspend all travel outside of the capital.
The new state of emergency will create a group of people with conflicting interests, Befekadu said. "It brings temporary silence but not normalcy".