TSKHINVALI, Georgia (Reuters) -- Two loud explosions were heard from the capital of Georgia's rebel South Ossetia overnight and each side accused the other of shelling, underscoring tensions a year since their five-day war.
No one was hurt in the blasts, which a Reuters reporter heard from the center of Tskhinvali.
Gunfire is an almost daily occurrence on the de facto border, which at its closest point runs just a few hundred metres from the southern edge of Tskhinvali.
Analysts warn of the risk of skirmishes boiling over into renewed hostilities in pro-Western Georgia, with tensions simmering ahead of next week's anniversary of the war.
The South Ossetian Interior Ministry said in a statement that two mortar rounds were fired towards residential buildings from the village of Zemo Nikozi, where Georgian police stand behind high sandbag walls ringing the village cemetery.
The Georgian Interior Ministry said the shooting came from Russian-backed South Ossetian forces in Tskhinvali, in the direction of Zemo Nikozi.
"It started with machine guns and then from large-calibre weapons, mortars," said ministry spokesman Shota Utiashvili. "We did not return fire."
Russia crushed a Georgian assault on Tskhinvali last August after weeks of escalating skirmishes, sweeping tanks and troops into Georgia proper to within 40 kilometers of the capital, Tbilisi.
Like the rebel Black Sea region of Abkhazia, South Ossetia threw off Georgian rule in wars in the early 1990s with the collapse of the Soviet Union.
The West, nerves rattled over energy transit routes running through the South Caucasus, accused Russia of a "disproportionate response." The European Union brokered a ceasefire, and deployed 240 unarmed monitors.
Russia recognised South Ossetia and Abkhazia as independent states, with thousands of Russian troops stationed in both regions despite the ceasefire calling for a withdrawal to pre-war positions.
The EU mission is denied access to either rebel region, and is now alone in monitoring the ceasefire after Russia forced the withdrawal of military observers of the United Nations and the Organization for Security and Cooperation in Europe.
An EU spokesman said the monitors were checking reports of shooting overnight, and were seeking contact with Russian forces through a "hot-line" established to help diffuse clashes.