Members of Ethiopia's National Intelligence and Security Service (Niss) were behind the 23 June blast at a rally attended by Prime Minister Abiy Ahmed, Attorney General Berhanu Tsegaye has said, news agency Reuters reports.

Two people were killed at the massive rally in Meskel Square in the capital, Addis Ababa.

In September, five suspects were charged with terrorism over an attempt to kill the prime minister.

Mr Berhamu also said arrest warrants had been issued for 36 security agents accused of rights abuses and corruption.

Warrants have also been issued for more than 30 officials from a military-run firm, Metals and Engineering Corporation( Metec).

"For six years Metec made international procurement totaling $2bn (£1.5bn) without any bidding processes," Mr Berhanu said, referring to the company's contract for building the Grand Renaissance Dam.

Since coming to power in April, Mr Abiy has launched several reforms, including freeing political prisoners and making peace with Eritrea.