VILNIUS (Reuters) - A member of Lithuania’s parliament is facing impeachment proceedings and an investigation into whether his ties to Russian business and media posed a threat to national security.

Lithuania’s parliament voted on Thursday to initiate the impeachment of Social Democrat Mindaugas Bastys after the country’s secret service refused to issue him with top security clearance.

Bastys has denied any wrongdoing.

The decision emphasized the nervousness in Lithuania about a perceived disruptive Russian influence in the country, which was annexed into the Soviet Union in the 1940s but regained independence as the union broke apart in the early 1990s.

The secret service said Bastys is vulnerable to influence due to his close personal relationships with people representing Russian state nuclear monopoly Rosatom, Russian gas trade monopoly Gazprom and Russian state television.

“Our conclusion is that Bastys’s ties and other circumstances give ground to doubt the trustworthiness of this person,” the head of the secret service said in a letter to the speaker, published on parliament’s website.

Bastys resigned from his post as deputy speaker following the allegations, but said he had not broken any laws and refused to give up his seat.

“I know that I did not commit any offences that would violate Lithuanian laws,” he was quoted as saying by the BNS news agency. Bastys did not immediately respond to Reuters’ request for comment.

The secret service said Bastys has acted to further the interests of his acquaintances, such as working in 2012-2013 to arrange a meeting between a Rosatom officer and then-Prime Minister Algirdas Butkevicius, a Social Democrat.

Rosatom is developing a nuclear power plant in Belarus next to the Lithuanian border. The Lithuanian government strongly objects to the plant.