Mindaugas Bastys, a former Social Democrat-turned-independent, announced his decision hours after Prime Minister Saulius Skvernelis had urged him to step down.
Lawmakers in the 141-seat Seimas were unsuccessful Tuesday in revoking Bastys' mandate for lying about his Russian connections after failing to reach the needed 85 votes for an impeachment.
Probes had concluded Bastys, who is suspected of liaising with shady Russian lobbyists, had acted against Lithuanian interests by working with Russians and breaching the constitution of Lithuania, a former Soviet republic. He has denied any wrongdoing.
Lithuania's secret service concluded Bastys had close personal relationships with people representing Russian state nuclear monopoly Rosatom and Russian state television. The Lithuanian government has strongly objected to two nuclear power plants being built by Rosastom in Belarus, south of the Baltic country, and in the Russian exclave of Kaliningrad, which shares a border with Lithuania, among others.
No criminal investigation against Bastys has been opened.
In recent years, Lithuania has deported several Russian nationals suspected of espionage. Lithuanians also have been convicted for spying for Belarus, which authorities say is sharing information with Russia.
In July, a court in Lithuania found a Russian national guilty of spying and sentenced him to 10 years in prison for attempting to recruit local officials to plant listening devices in the offices of the Baltic nation's president.
In 2004, Lithuania impeached its then president Rolandas Paksas for allegedly having close links to Russian business people.
Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.