Ethiopia's Prime Minister Abiy Ahmed said the country's chief of staff had been shot dead after riots in the North Amhara region.
Abiyon appeared on television and said several officials were killed in an attack in Ethiopia. The capital of the Amhara region, Bahir Dar.
Earlier, the government stated that a "coup attempt" had taken place in Amhara.
According to reports, the Internet has failed in the country.
Inhabitants of Bahir Dar reported heavy gunfire.
The US State Department said it also has reports of gunfire in the state capital of Addis Ababa.
Mr. Ahmed was elected last year and has ended political repression in Ethiopia by releasing political prisoners and repealing political bans. Parties and prosecutors are being charged with violations of rights.
But since he came to power, ethnic violence has reappeared, leaving behind 2.4 million displaced Ethiopians, according to the UN.
Mr. Abiy said Chief of Staff Seare Mekonnen has been attacked by "mercenaries".
He gave no details about his condition.
He also said that some officials in Amhara had been in a meeting when they were shot "by their peers".
Abiy spokesman Negussu Tilahun said the rebels had tried to overthrow Amhashev Mekonnen, head of the Amhara regional government.
In a statement, the ruling party in Amhara accused a former security chief who was released from prison after Mr. Abiy came to power behind the violence.
A lecturer in Bahir Dar told Reuters that the shots in the city lasted at least four hours.
"At first I thought it was just a normal incident, and then we heard violent shots," he said.
The scheduled Sunday events have been canceled, said the state television.