ANALYSTS' VIEW: Security experts on South Ossetia fighting

LONDON (Reuters) - Russia sent forces into Georgia on Friday to repel a Georgian assault on the breakaway region and Georgia's pro-Western president said the two countries were at war.

Here are comments from defence and political analysts on the escalating crisis:

CHRISTOPHER LANGTON, DEFENCE ANALYST AT INTERNATIONAL INSTITUTE FOR STRATEGIC STUDIES AND EXPERT IN CENTRAL ASIA:

"It's very hard to tell how serious it is at this point. Although TV pictures tend to show Russian armor moving into South Ossetia, we don't know for sure.

"If that were to be the case, this would be the most serious incident in South Ossetia since the end of the war and it changes the face of this conflict quite dramatically.

"There is now real danger of Georgian and Russian forces clashing in a serious fashion.

"I'm still a bit puzzled as to why this has gone so far, given the risks to Georgia in terms of the possibility of not being able to fulfill its aspirations towards NATO and the EU.

"Russia has a military capability, if it is indeed moving into South Ossetia, to secure a corridor from Tskhinvali back through the Roki tunnel and to secure Tskhinvali itself," he said, referring to a tunnel that is the only land route connecting South Ossetia to the Russian Federation. Tskhinvali is the main city in South Ossetia.

"The biggest danger would be if fighting broke out in the city itself."

SVANTE CORNELL, CO-DIRECTOR OF THE STOCKHOLM-BASED INSTITUTE FOR SECURITY AND DEVELOPMENT POLICY AND AN EXPERT ON GEORGIA:

What are the roots of the conflict?

"It boils down to Kosovo independence, NATO's Bucharest summit and possibly also Russian internal politics and the transfer of power.

"In February, Russian diplomats said Kosovo's unilateral declaration of independence from Serbia would stir up strife in the Balkans and linked Kosovar status to separatist areas Abkhazia and South Ossetia."

Cornell said Russia has seized upon a moment to assert itself in South Ossetia when Europe is unwilling to anger Moscow, the United States is distracted by domestic elections and Georgia has perhaps fallen into an Ossetian provocation.

"Irrespective of who triggered this recent action, the general direction of Russian policy is clear, which is: We are taking control of these territories, and we're not even pretending that we're not."

PAVEL FELGENHAUER, SECURITY ANALYST: