Jonas Paulikas, 39, a major in the security department charged with guarding high-ranking officials, opened fire at the popular restaurant in downtown Vilnius in the early hours of Wednesday, police said.
No one was hurt, although the chef had been in the kitchen at the time.
Paulikas was detained after the incident, and his handgun - a Sig Sauer - was confiscated.
Police said Paulikas was heavily intoxicated at the time. He was hospitalized and claims he does not remember the incident.
Restaurant managers declined to comment.
Paulikas is considered to be a veteran in the security department. Algirdas Brazauskas, former president and prime minister who was under Paulikas' protection for almost 15 years, expressed shock at the news. "I would have never believed that he is capable of such behavior. Paulikas is a decent man and a very good officer," Brazauskas said.
Police have launched an investigation.