TBILISI, Georgia -- Tensions in Georgia's breakaway region of South Ossetia flared Sunday after separatist officials said three police officers had been wounded in a nighttime attack and blamed the incident on the central government.

A spokesman for South Ossetia's unrecognized regional government said assailants had opened fire from a Georgian-controlled village on police posts in the regional capital Tskhinvali with mortars and grenade launchers.

Three policemen were wounded, two seriously, said the spokesman, Andrei Tatayev.

"This is a provocation by a Georgian sabotage group," Tatayev said.

Georgian authorities denied any involvement in the attack.

"There is a version that this is an internal settling of scores between South Ossetian illegal armed groups," said Mamuka Kurashvili, commander of Georgian peacekeeping forces in the region.

Kurashvili said a joint group comprising separatist and Georgian sides, Russian peacekeepers and international monitors would investigate the incident.

Since a 1992 cease-fire ending fighting between Georgian and South Ossetian forces, the territory has been in a tense limbo -- officially part of Georgia but under the control of an internationally unrecognized government that seeks to make South Ossetia part of Russia.