BANGKOK, July 20 (Reuters) - Militants fired on an army outpost and killed three villagers in separate attacks in Thailand's restive Muslim south, police said on Sunday, days after an unknown rebel group declared a ceasefire.

One soldier was wounded when a grenade exploded at the outpost late on Saturday in Pattani, one of three southernmost provinces where more than 3,000 people have been killed in separatist attacks since 2004.

Also in Pattani, three Muslim villagers were shot dead by suspected militants, police said.

Thai authorities feared a spike in violence after the unknown Thailand United Southern Underground announced a "ceasefire" last week that was dismissed by army officials and security experts who said its leaders had no influence in the region. The Thai army identified the group's leader as Malipeng Khan, a separatist active in the 1980s who had failed to unify insurgent factions in the region annexed by predominately Buddhist Thailand a century ago.

Since the latest violence erupted in 2004, the shadowy rebels have never revealed themselves publicly or claimed responsibility for the near daily gun and bomb attacks in the rubber-producing region bordering Malaysia.

Thai media attention has focused on Chettha Thanajaro, a former defence minister and leader of a minor party in Thailand's coalition government, who announced the "breakthrough" on Thursday after a year of talks with 11 separatist groups.

"It was somewhere between a cheap political ploy aimed at putting pressure on the Malay Muslim insurgents in the deep south, or a desperate bid for free publicity," the Nation newspaper said in an editorial on Friday.

"Either way, former army chief-turned-politician Chettha Thanajaro ... has raised more questions that he has answered." (Reporting by Surapan Boonthanom; Editing by Darren Schuettler and Alex Richardson)

AlertNet news is provided by