Bulgaria's foreign ministry told Russia in an official note Friday that it had not yet held any talks on joining a planned US missile shield in Europe, the ministry said in a statement.

The note answered an official request for explanation from the Russian foreign ministry received earlier Friday.

Bulgaria "confirmed once again that no official talks for hosting elements of an anti-missile defence (system) on Bulgarian territory have been held to this date."

"As a NATO member, Bulgaria will continue to strictly adhere to the joint approach to decision-making within NATO in the area of security, including (matters) related to anti-missile defence," the foreign ministry added.

Bulgarian Prime Minister Boyko Borisov said last week that he favoured taking part in a US missile shield, angering Russia, which opposes US plans to station missile defences in the former Communist countries of eastern Europe.

The US has also said it is open for talks with Sofia on the issue.