Ethiopia's Nobel Peace Prize-winning Prime Minister Abiy Ahmed has declared a state of emergency in the restive Tigray region in response to an alleged attack by the Tigray People's Liberation Front (TPLF) on a federal military base.

"This situation has reached a level where it cannot be prevented and controlled through the regular law enforcement mechanism," a statement from Abiy's office said Wednesday.

The state of emergency will last for six months and be overseen by a task force led by the head of the army.

The decree gives the federal government broad powers to "protect the country's peace and sovereignty, and to maintain public security, law and order," including suspending political and democratic rights, according to the Ethiopian constitution.

The statement was released hours after the prime minister ordered a military operation in the region earlier on Wednesday.

"The federal government has used all means to thwart a military engagement against the TPLF" amid growing tensions between the federal government and the ruling party of the Tigray region, but "the last red line has been crossed," an earlier statement read.

Abiy vowed the mission would "save the country and the region from spiraling into instability."

Details of the attack on the military base remain unclear, but Abiy accused the TPLF of attempting to "rob" the base of artillery and military equipment.

Abiy's office said the TPLF had been manufacturing military outfits resembling those of the Eritrean National Defence Forces to implicate the Eritrean government in false claims of aggression.

Internet services in the Tigray region were shut down from 1 a.m. local time Wednesday, according to internet-monitoring group Netblocks.

"We join the international community in calling for immediate de-escalation in Tigray," said the UK embassy in Ethiopia in a tweet Wednesday. "We urge all sides to keep civilians safe."

The US embassy also urged de-escalation and "strongly" encouraged "all parties to prioritize civilians' safety and security."

The TPLF dominated Ethiopia's ruling coalition for nearly 30 years before mass anti-government protests led Abiy into power in 2018. Tensions between the party and the federal government have risen in recent months over regional and national elections and military assets stationed in the Tigray region, according to the International Crisis Group.

Earlier this year, the Ethiopian government indefinitely postponed all elections previously planned for August due to the coronavirus pandemic. The Tigray region decided to hold its own regional elections in September, which the federal government branded "illegal."

Abiy's domestic record was not why he was awarded the prestigious Nobel prize last year. According to the committee, he was chosen for "his decisive initiative to resolve the border conflict with neighboring Eritrea," resulting in a peace deal they hope "will help to bring about positive change for the entire populations of Ethiopia and Eritrea."