Ethiopia on Thursday objected to a speech delivered by the US ambassador urging better protection of human rights, with the foreign ministry calling the address "unsolicited" and "ill-advised".

While visiting a recently restored historical building in capital Addis Ababa on Wednesday, Ambassador Ervin Massinga called for a "transparent transitional justice process" to address reports of extrajudicial killings, arbitrary detentions, sexual violence and other abuses.

"To those whose responsibility it is to govern Ethiopia, the government here, the country has far more to gain through peace than on the battlefield," he said.

"Detaining and harassing those who criticise the government will not resolve those issues that must be addressed," he added.

Ethiopia's Ministry of Foreign Affairs denounced the speech on Thursday, saying it contained "allegations against, and unsolicited advice to the Government of Ethiopia."

"The statement is ill-advised and contains uninformed assertions. It is contrary to the historic and friendly relations between Ethiopia and the United States," the ministry said in a statement.

In his speech, Massinga blamed "all armed actors" for inflicting human suffering in the country, including by displacing civilians.

He called on fighters from various armed ethnic factions, including the Oromo Liberation Army -- which the government considers a "terrorist organisation" --  the Fano self-defence militia and the Tigray People's Liberation Front to make their demands through dialogue rather than violence.

A mosaic of more than 80 ethno-linguistic communities, Africa's second most populous country has endured multiple conflicts over identity and territorial claims in recent years.