CLASHES in southern Kyrgyzstan have spiraled out of control. Thus far 118 people have been confirmed dead, a further 1,500 as injured, and tens of thousands of ethnic Uzbeks have fled to neighbouring Uzbekistan. The number of those killed over the past four days are without a doubt significantly higher than these estimates suggest. Local Muslim custom requires that the dead are buried within 24 hours. Many people are burying family members immediately without registering their deaths.

Although Uzbeks make up only 15% of Kyrgyzstan's population of 5.4m, most of them live in the southern part of the country, where they make up the majority. The Fergana Valley, where most of the killing happened, was divided arbitrarily by Stalin in the 1920s among Uzbekistan, Kyrgyzstan and Tajikistan. As a result, the Kyrgyz Soviet republic was left with a sizeable Uzbek population, the Uzbek Soviet republic with a Tajik population, and so on. While the Soviet Union existed and the republics were part of the same country, this made little practical difference. But when the Soviet Union fell apart, these artificially created borders became final, separating newly independent states and fomenting ethnic tensions.

The interim government has been powerless to put an end to the violence. Roza Otunbayeva, the acting president said that the country needed outside help and appealed to Russia to send peacekeeping troops. Security officers were given shoot-to-kill orders. The Russian government initially responded that the violence was an internal affair for Kyrgyzstan to handle on its own and agreed only to send humanitarian aid. A day later Russia dispatched paratroopers to secure its Kant military base in the northern part of the country. The United States also has an air base in the north, but has not been invited to intervene with its military forces.

The cause of the rampage involving Kyrgyz and ethnic Uzbeks, which began in Osh, Kyrgyzstan's second-largest city, remains unclear. Observers believe that the events were orchestrated by individuals taking advantage of long-standing tensions between the two ethnic groups. The interim government has blamed ex-president Kurmanbek Bakiyev and his supporters. It says they instigated the unrest to prevent a national referendum on its proposal for a new constitution, which was scheduled to be held on June 27th. Mr Bakiyev, who was ousted in a popular uprising in April and now lives in exile, has rejected the charge.

This wave of violence has been shaped by politics. Mr Bakiyev hails from the south of the country. His stronghold was in Jalal-Abad, where he still has many supporters. Ethnic Uzbeks, who play almost no role in Kyrgyzstan's public life—whether in government, regional administrations, or the military—have tended to prefer the interim government, which has set its sights on turning Kyrgyzstan away from authoritarian presidential rule to a parliamentary republic.

Whatever the cause, the fighting between ethnic Kyrgyz and Uzbeks has been ferocious. Some eye witnesses claim that the army, which consists mainly of ethnic Kyrgyz, has sided with its kin. Violence spread to Jalal-Abad over the weekend. Although atrocities appear to have been committed by both sides, the Kyrgyz quickly gained the upper hand. Uzbek houses have been looted and set on fire—plumes of smoke are visible for many miles around—women have reportedly been raped, and armed Kyrgyz gangs have been harassing and shooting at Uzbeks. Gas was shut off in much of Osh, as was electricity in some quarters. Shops have been ransacked and food has become scarce.

Many ethnic Uzbeks, mostly women, children and the elderly, have fled the city to the nearby border with Uzbekistan, looking for safety. According to official Uzbek figures, 32,000 people have so far crossed the border and now live in make-shift tents. Unofficially, at least 75,000 people are believed to have fled the country. An NGO based in Uzbekistan says that there are already more than 200,000 Uzbek refugees sheltering there.

“It is a human-rights disaster in every respect,” says Andrea Berg, a researcher with Human Rights Watch, a New York-based organisation, who happened to be in Osh when the rioting started. She says she received many desperate phone calls from people unable to get out of the city because of blockades erected by Kyrgyz gangs. Those Uzbek women and children who made it are now gathering in different villages along the border and do not know what has happened to their husbands, brothers and fathers.

The current clashes are the worst ethnic violence in Central Asia in 20 years. In June 1990 clashes between Kyrgyz and ethnic Uzbeks in the Osh region left several hundred people dead. That conflict was resolved through the quick deployment of Soviet troops. Its suppression was enforced by Askar Akayev, who ruled as Kyrgyzstan's president until 2005, when the “tulip revolution” saw him replaced by Mr Bakiyev.