Russia says it is asking Bulgaria to explain its plans to deploy US air defence missiles on its soil. The move follows reports that talks between Sofia and Washington on hosting elements of the US missile shield in Bulgaria have already begun. Last week the Bulgarian Prime Minister said he was keen to join the US shield. At a meeting in Moscow yesterday, Russian Deputy Foreign Minister Vladimir Titov told Bulgaria's ambassador to Russia, Plamen Grozdanov, it would seek an explanation as to the goals and essences of its talks with the US.