Police and soldiers struggled Saturday to stop ethnic clashes in this Central Asian country that have killed more than 50 people, as gangs of armed young Kyrgyz men marched on Uzbek neighborhoods and fires raged throughout the city. The official death toll has climbed to at least 51, while about 700 people have been wounded, the Health Ministry said. The real figures may be higher because doctors and human rights workers said ethnic Uzbeks were afraid to seek hospital treatment. Thousands of ethnic Uzbeks were fleeing toward the nearby border with Uzbekistan, the Associated Press reported. The violence that broke out Friday in Osh, the country's second-largest city, is the worst since former President Kurmanbek Bakiyev was toppled in a bloody uprising in April and fled the country. It poses a decisive test of the provisional government's ability to control the country, where the U.S. and Russia both have military air bases. The government needs stability to hold a June 27 vote on a new constitution and go ahead with elections for a new parliament in October. The government declared a state of emergency in and around Osh and dispatched armored vehicles, troops and helicopters to pacify the situation. Fighting quieted down overnight but resumed with new strength Saturday. Much of central Osh was on fire, while homes in Uzbek neighborhood also burned.