Moscow waits for detailed explanations concerning U.S. plans to deploy elements of its missile shield in Bulgaria, the Russian foreign minister said.

"I repeat that we are waiting for detailed explanations, which have been promised to us," Sergei Lavrov said upon his arrival to Nicaragua for a one-day official visit.

James Warlick, the U.S. ambassador to Bulgaria, said earlier in the week that the United States was holding informal talks with the Balkan country on hosting elements of a U.S. missile shield on its soil.

"We have already asked our partners in Washington... what does this all mean and why after the Romanian 'surprise' there is a Bulgarian 'surprise' now," Lavrov said.

Last week Romania announced that it would host interceptor missiles as part of a U.S. missile defense system on its soil.

A U.S. State Department official said earlier the facilities in Romania are to become operational by 2015 and are designed as protection against "current and emerging ballistic missile threats from Iran."

The planned deployment in Romania comes after U.S. President Barack Obama scrapped plans for a radar and interceptor missiles in the Czech Republic and Poland, which Russia fiercely opposed as a national security threat and a blow on its nuclear deterrent. Moscow threatened retaliatory measures.

MANAGUA, February 14 (RIA Novosti)