World leaders, as well as international organizations, have called for an end to fighting in Georgia's breakaway region of South Ossetia. VOA's Senior Correspondent André de Nesnera has this report from Washington.

South Ossetia along with another Georgian region - Abkhazia - declared their independence from Georgia in the mid 1990s. Georgia's president Mikhail Saaakashvili has vowed to bring both regions back into the fold.

Tensions between Georgia and Russia have escalated over the years as Moscow increased economic, commercial and political ties with the two breakaway regions. Over the past few months, tensions increased significantly as Tbilisi and Moscow took a series of military measures in the region: Moscow sent warplanes over the two regions and increased its military buildup in the area.  Tbilisi responded in kind and sent unmanned reconnaissance planes over the breakaway regions.

"The sides of the conflict have been playing a kind of cat and mouse game for a couple of years now and they've always kind of pushed each other to the brink but then pulled back," said Sabine Freizer with the Brussels-based International Crisis Group. "Unfortunately, that's not what happened [in the past 24 hours] and what we've seen is a large scale military offensive throughout South Ossetia."

Freizer called on both sides to address the humanitarian situation in the area.

That appeal was echoed by United Nations spokeswoman Michele Montas  who described the conditions in South Ossetia as related by a worker for the U.N. High Commissioner for Refugees.

"A UNHCR staff member in that area has reported that many buildings and houses have been destroyed and that only military personnel are moving in the streets," said Montas. "Water is in short supply. Most transport has stopped and shops are running out of food."

Analysts, including Jason Lyall from Princeton University's Woodrow Wilson School for Public and International Affairs, say if the conflict escalates to a full-blown war between Georgia and Russia, Tbilisi has very little chance of winning.

"Russia has about 100,000 troops in the region just because it's so heavily militarized from Chechnya and the other insurgencies that are going on next door," he said. "If this is a long war, Georgia will be in a considerable amount of trouble just because its forces are so much smaller: it only has about 27,000 soldiers and it would rely also on these militia groups that it is starting to reactivate as well. But in a long war Georgia would be in trouble."

NATO Secretary-General Jaap de Hoop Scheffer called on all sides to bring an immediate end to the armed clashes in South Ossetia and begin direct talks between all parties.

That view was echoed by world leaders as Russian tanks and troops entered Georgia's breakaway region after Tbilisi launched a military offensive to reclaim South Ossetia.

As president of the European Union, France said it was working towards a ceasefire, reaffirming its commitment to Georgia's territorial integrity and sovereignty.

Members of the United Nations Security Council also met in an effort to head off further bloodshed.

Analysts say the international community must react quickly now to first secure a ceasefire and then seriously address how to resolve the seemingly intractable question of what to do with South Ossetia and Abkhazia.