SOFIA (Reuters) - Bulgaria will not expel Russian diplomats in response to a nerve agent attack in England that the British government has blamed on Moscow, its prime minister said on Friday.

FILE PHOTO - Bulgaria's Prime Minister Boyko Borissov addresses the European Parliament in Strasbourg, France, January 17, 2018. REUTERS/Vincent Kessler

Boyko Borissov said the Black Sea country, as a current chair of the European Union presidency, needed to keep dialogue open with Russia amid an escalating standoff between the West and Moscow over the nerve agent attack on March 4.

After the first known use of a military-grade nerve agent on European soil since World War Two, most EU and NATO members, including the United States, have expelled Russian diplomats.

Several EU countries, including Greece, Cyprus, Portugal, Slovenia and Austria, however, have not joined the coordinated action.

Bulgaria has expressed its solidarity with its EU and NATO allies by recalling its ambassador from Moscow for consultations, Borissov said, but stressed that more evidence was needed for further action.

“As chair of the European Council we must keep the communication channel (open), as we have done in times of an over-tensed situation in our region at present with Turkey. We must do the same with Russia,” Borissov said.

“At this stage, we do not think we should expel Russian diplomats and officials,” Borissov said, after a meeting of the government’s security council over the nerve gas attack that included a hearing of the Bulgarian ambassador to Moscow.

Borissov said the ambassador will return to Russia after the Orthodox Easter on April 8.

Calls for Bulgaria to expel Russian diplomats have faced strong opposition both in the coalition government as well as in other political parties in parliament which favor pursuing good ties with Russia.

Bulgaria, which was liberated from Ottoman rule by Russia, became one of the most obedient Soviet satellite states during the Cold War. Many Bulgarians feel a strong cultural affinity for Russia, with which they share the Cyrillic script and orthodox Christianity.

Bulgaria is also almost fully reliant on Russian gas supplies, military equipment and tourism revenues.