Ethiopia's new PM Abiy Ahmed described it as an "unsuccessful attempt by forces who do not want to see Ethiopia united".
According to the media, the explosion happened in Meskel Square in Ethiopia's capital, Addis Ababa, after Prime Minister Abiy Ahmed finished addressing the crowd of his supporters and was going to leave the stage waving to people.
Local media published alleged photos of the incident and reported that it was a hand grenade thrown at the police car.
The 42-year-old Abiy took office in April and quickly surprised Africa's second most populous country by announcing a wave of political and economic reforms.
