Uzbeks fleeing ethnic violence in Kyrgystan gather near its southern border, hoping to cross into Uzbekistan. (D. Dalton Bennett/Associated Press)

Ethnic riots wracked southern Kyrgyzstan on Saturday, forcing thousands of Uzbeks to flee as their homes were torched by roving mobs of Kyrgyz men. The interim government begged Russia for troops to stop the violence, but the Kremlin offered only humanitarian assistance.

At least 77 people were reported killed and more than 1,000 wounded in the violence spreading across the impoverished Central Asian nation that hosts U.S. and Russian air bases.

Much of its second-largest city, Osh, was on fire Saturday, the sky overhead black with smoke. Roving mobs of young Kyrgyz men armed with guns and metal bars marched on minority Uzbek neighbourhoods and set homes on fire, forcing thousands of Uzbeks to flee. Stores were looted and the city was running out of food.

Kyrgyzstan's third straight day of rioting also engulfed another major southern city, Jalal-Abad, where a rampaging mob burned a university, besieged a police station and seized an armoured vehicle and other weapons from a local military unit.

"It's a real war," said local political leader Omurbek Suvanaliyev. "Everything is burning, and bodies are lying on the streets."

Those driven from their homes rushed toward the border with Uzbekistan, and an Associated Press reporter there saw the bodies of children trampled to death in the panicky stampede. Crowds of frightened women and children made flimsy bridges out of planks and ladders to cross the ditches marking the border.

Interim president Roza Otunbayeva acknowledged that her government has lost control over Osh, a city of 250,000, even though it sent troops, armour and helicopters to quell the riots.

"The situation in the Osh region has spun out of control," Otunbayeva told reporters. "Attempts to establish a dialogue have failed, and fighting and rampages are continuing. We need outside forces to quell confrontation."

Otunbayeva asked Russia early Saturday to send in troops, but the Kremlin said it would not meddle into what it described as Kyrgyzstan's internal conflict.

"It's a domestic conflict, and Russia now doesn't see conditions for taking part in its settlement," Kremlin spokeswoman Natalya Timakova said in Moscow. She said Russia will discuss with other members of a security pact of former Soviet nations about the possibility of sending a joint peacekeeping force to Kyrgyzstan.

Crucial supply hub for U.S.

Russia has about 500 troops at a base in Kyrgyzstan, mostly air force personnel. The United States has the Manas air base in the capital, Bishkek, a crucial supply hub for the coalition fighting the Taliban in Afghanistan.

Kyrgyzstan's interim government spokesman, Farid Niyazov, refused to say whether the country would turn to the U.S. for military help after Russia had refused. "Russia is our main strategic partner," he said.

The riots are the worst violence since the former president, Kurmanbek Bakiyev, was toppled in a bloody uprising in April and fled the country.

Otunbayeva on Saturday blamed Bakiyev's family for instigating the unrest in Osh, saying they aimed to derail a referendum the interim government wants to hold on June 27 to vote on a new constitution, followed by parliamentary elections in October.

Maksat Zheinbekov, the acting mayor of Jalal-Abad, said in a telephone interview that Bakiyev's supporters in his home region started the riots by attacking both Uzbek and Kyrgyz. The rampaging mob quickly grew in size from several hundred to thousands, and automatic gunfire echoed through the city, he said.

Ethnic tensions have long simmered in the Ferghana Valley, split by Soviet dictator Josef Stalin's whimsically drawn borders among Uzbekistan, Kyrgyzstan and Tajikistan.