Lithuanian special forces raided a news office on Nov. 7 over allegations that journalists had gained access to classified material.
Six journalists from the Baltic News Service (BNS) in Vilnius were questioned while computers were confiscated. The BNS editors home was also searched, the news agency reports.
It's understood the journalists have since been released.
Alvis Eglitis, foreign news editor with BNS in Latvia told the Baltic Times that the journalists had gained access to a classified document from the Lithuanian State Security Department showing evidence that Russia was planning a smear campaign against Lithuania President, Dalia Grybauskaite.
A spokeswoman from the Lithuanian Special Investigation Service declined to comment on details but confirmed that an investigation is currently underway.
A statement from BNS read:
"BNS, the largest news agency in the Baltic states, condemns the pressure exerted by law-enforcement institutions, which violates the rights of journalists to keep their information sources secret.
"In the framework of a pre-trial investigation, a judge instructed a BNS editor to reveal her source of information. The Special Investigation Service searched the BNS editor's home, summonned six BNS employees to interrogation and seized a few computers.
"Such scale of unprecedented procedural measures of violence interrupted BNS operations and are, furthermore, disproportionate and unacceptable. Persecution of the media is characteristic of undemocratic countries. A journalist's right to keep his source of information secret is one of the guarantees of free press. BNS will exercise the right and will not reveal the source of information."
BNS intends to turn to the prosecutor general and the head of the Special Investigation Service for explanation.