* Aide charged with leaking about alleged Russian smear plan
* Media, politicians have criticised investigation
* President has said to decide prosecutor's future
By Andrius Sytas
VILNIUS, June 23 Lithuania's presidential spokeswoman was charged on Monday with leaking secret intelligence to the media, in a decisive step by prosecutors whose months-long investigation has been sharply criticised by journalists and politicians.
Prosecutors have searched the homes and tapped the phones of several journalists and have tried to question President Dalia Grybauskaite to find out who leaked an intelligence report that said Russia was preparing to smear her.
Grybauskaite, who has many times in the past criticised Prosecutor General Darius Valys and has suggested his position is at risk, declined to be questioned, citing immunity.
"We have not determined this (that the president has been involved) so our decision is to file the criminal case with the court and have one person accused of revealing a state secret," prosecutor Gintas Ivanauskas told reporters after the spokeswoman, Daiva Ulbinaite, was charged.
The investigation centres around a report last October by the Baltic News Service (BNS) which cited an intelligence report that said the Kremlin was planning to discredit the president of the former Soviet state by publishing false information about her.
The investigation was started after a complaint by Lithuania's intelligence service, which authored the secret report. The agency said its sources might have been compromised by the leak.
Ulbinaite denies all charges, her lawyer, Giedrius Danelius, told Reuters. She faces up to three years in jail for revealing state secrets and an abuse of office charge that could be punished by up to five years.
Ulbinaite has stepped down while the legal process continues. The president refused to fire her in December when reports of her involvement first surfaced and she said the intelligence report was not sensitive enough to be marked as secret in the first place.
Moscow has not reacted to the report.
The Kremlin was angered by Grybauskaite's push to get an association treaty between Ukraine and the European Union signed in Vilnius, when Lithuania had the rotating EU presidency, BNS reported. Ukraine's then-president, Viktor Yanukovich, refused to sign the treaty, leading to mass protests and eventually his downfall.
Grybauskaite, a former EU commissioner, has said she would determine whether the chief prosecutor and the head of intelligence were fit to continue to serve after she takes her oath for a second term next month, after a landslide victory in elections in May. (Editing by Robin Pomeroy)