Several people were wounded overnight in Georgia`s rebel region of South Ossetia, officials from both sides said on Thursday, in fighting that has grown more intense since the weekend, according to Reuters.

Russia accused Georgia of preparing for war against its breakaway region and expressed concern over the situation.

Tensions between ex-Soviet Georgia and its two breakaway regions, South Ossetia and the Black Sea region Abkhazia, have increased in recent months.

Both regions broke away from Georgia in the early 1990s. Both have financial and political support from Moscow and the vast majority of locals have Russian citizenship.

Moscow and the West are vying for influence over vital energy transit routes in the region, and Georgia has angered Russia by pushing for membership of NATO.

Georgia and South Ossetia accused each other of starting the latest fighting.

"Separatists opened fire from different locations aiming at eight Georgian villages," Georgian Reintegration Minister Temur Iakobashvili told Reuters. "After several appeals to cease fire, and no response, the Georgian side had to return fire."

Two members of the Georgian security forces were wounded and some firing came from near Russian peacekeeping posts, he said.

The South Ossetian authorities said on the region`s website that 18 people were injured by a heavy artillery bombardment of villages and the capital Tskhinvali.

"As a result of overnight firing by Georgian military units against the Republic of South Ossetia 18 injured were brought into the hospital," the website said.

Russia, which said this week it would not be indifferent if violence escalated on its border, accused Georgia on Thursday of preparing for war against South Ossetia.

"Concern was expressed that the action of the Georgian side around Tskhinvali can be regarded as war preparations," the ministry said on its website after a telephone conversation between Russian Deputy Foreign Minister Grigory Karasin and South Ossetia`s leader, Eduard Kokoity.

Russia has previously accused Georgia of building up its military forces around South Ossetia and Abkhazia, allegations Georgia denies.

The United States, Georgia`s main ally, urged the two sides on Wednesday to halt the violence and resume negotiations but it was unclear if talks between South Ossetian and Georgian officials planned for Thursday would go ahead.

Russia`s special envoy Yuri Popov -- sent to Tbilisi at late notice on Wednesday -- told Rossiya television he still expected the two sides to meet. "If they don`t, I will conduct shuttle diplomacy as I have done in the past."

At the weekend six people died in fighting in villages around Tskhinvali, South Ossetian officials said.