BISHKEK (Reuters) - Kyrgyzstan, home to a U.S. military base, threatened to expel two American diplomats on Wednesday after accusing them of interfering in the Central Asian state's domestic affairs.

The U.S. embassy in the Kyrgyz capital Bishkek declined to say whether or when they might leave the country. The Kyrgyz Foreign Ministry said the diplomats were no longer welcome.

"The decision was taken based on facts presented by Kyrgyzstan's special services about their repeated involvement in the country's domestic affairs," it said in a statement.

A source in the Foreign Ministry told Reuters separately the diplomats were likely to be deported soon.

"They have to leave Kyrgyzstan as soon as possible. But we don't know when. ... It could be 24 hours, it could be 48 hours or it could be a month," the source said.

A row between Kyrgyzstan and the United States is a boon for Russia which is concerned about U.S. military presence in Central Asia, Moscow's traditional sphere of influence.

Kyrgyzstan has been in talks with Washington over raising the rent of the military airbase that the United States uses to support operations in nearby Afghanistan.

A fresh round of talks on the base was expected to start this week.

A U.S. embassy statement on Tuesday said the United States was "disturbed by reports" of the diplomats' expulsion.

It said the two were accused of "inappropriate contact" with non-governmental organizations and that Kyrgyzstan's move was an attempt to silence "the voice of civil society".

President Kurmanbek Bakiyev was elected in a landslide following a coup last year, raising hopes for greater democracy in the impoverished country of 5 million.

In April Bakiyev, accused by some opponents of not doing enough to maintain law and order, blamed unspecified foreign forces of trying to stoke unrest in his country.