Ethiopia’s Prime Minister, Abiy Ahmed addresses a news conference in his office in Addis Ababa. File picture: Kumera Gemechu/Reuters

Addis Ababa, Ethiopia - Ethiopia's attorney general has filed terrorism charges against five people accused of trying to "kill the prime minister" at a huge rally in the capital in June.

The charges filed Friday say the five acted on the premise that reformist Prime Minister Abiy Ahmed is not popular among Oromos, Ethiopia's largest ethnic group, and wanted to pave the way for the once-banned Oromo Liberation Front.

The group's leaders recently returned after Abiy's government invited all exiled groups to participate in politics.

A bomb thrown at the stage while Abiy waved to the crowd killed two people and wounded more than 150. Some collaborators remain at large, the state-affiliated Fana Broadcasting Corporate reports.

Ethiopians rally in solidarity with Prime Minister Abiy Ahmed, before a deadly explosion struck the huge rally in Meskel Square in Addis Ababa in June. File picture: Mulugeta Ayene/AP

Abiy is Ethiopia's first prime minister from the Oromo ethnic group.

Ethnic tensions are threatening his sweeping reforms.