Bulgaria and the US signed what they called “key documents” related to nuclear energy for civilian purposes, making the eastern European country the third in recent weeks to sign a nuclear energy-related agreement with Washington.

A statement by Bulgaria’s council of ministers quoted prime minister Boyko Borisov as saying nuclear energy is one of the greener and cleaner energies and that is why “we want to use more secure technology of the latest generation and achieve the diversification of nuclear fuel”.

The statement said the agreement had been signed by energy minister Temenuzhka Petkova and the US State Department’s Christopher Ford. Ms Petkova said the agreement will provide “a new impetus and a good basis for future energy cooperation between the two countries”.