BRUSSELS (AP) — NATO's secretary-general says that no one has the right to try to stop Montenegro from joining the military alliance or interfere with elections in the Balkans state.

Jen Stoltenberg said Wednesday that only NATO's 28 members and Montenegro can decide its membership. He said "it's up to us to decide, and we have decided to invite Montenegro."

Two Russians and three Serbians are among 21 people linked to an alleged election-day plot in Montenegro to assassinate the prime minister and take power because of its NATO membership bid.

Stoltenberg said "any interference into elections in any sovereign nation is absolutely unacceptable."

He welcomed investigations in Montenegro and Serbia into the suspected plot. He underlined that Montenegro's accession process is moving forward and that the country would join soon.