Ethnic clashes that killed at least 191 people have exposed the authorities’ lack of control over the south and although the unrest has subsided, the root causes are far from resolved, analysts said.

After the chaos in Kyrgyzstan, the unrest also risks spilling over into the introvert neighbouring state of Uzbekistan and impoverished Tajikistan, both of which share borders with Afghanistan.

Kyrgyzstan’s interim authorities led by former foreign minister Roza Otunbayeva surged to power this year after popular protests ousted President Kurmanbek Bakiyev.

Even before the clashes in the south, the government struggled to impose its authority and in May pro-Bakiyev supporters seized key regional buildings in the south.

Its lack of authority has created a dangerous power vacuum in a country that has seen growing Islamism in recent years, a gap some believe can only be filled by international peacekeepers.

“The south is almost in a state of anarchy. But if the armed bandits, even if it is just 700-2,000 of them head towards the north, anarchy is possible in all the country,” said Daniil Kislov, editor-in-chief of the Ferghana.ru news website.

“If the north of Kyrgyzstan is affected, it then risks spreading to Kazakhstan, the north of Uzbekistan, creating a major conflict in Central Asia.”

The cities of Osh and Jalalabad hit by the violence lie in the Ferghana Valley, a tinderbox region that has been fought over for two millenia by a succession of empires.

The region is now shared between Kyrgyzstan, Tajikistan and Uzbekistan and its modern-day borders — inherited from seemingly arbitrary demarcation under Stalin — do not reflect the concentrations of ethnic groups.

Alexei Malashenko, an expert on the region at the Carnegie Moscow Centre added: “It’s anarchy in the south, the authorities can do nothing there. And those who carried out the massacres could go to the north.”

“The spectre that we feared — a cauldron of radicalism and extremism — has come to life.”

Demonstrations in the Uzbek city of Andijan near the Kyrgyz border five years ago were violently suppressed by security forces, with dozens killed, according to rights groups.

Kyrgyzstan has always been seen by far the most volatile of the ex-Soviet republics of Central Asia and the only one to have embraced a semblance of pluralistic democracy in a region of authoritarian strongmen.

Meanwhile, an ethnically-mixed population, which includes 14 percent of Uzbeks and a similar number of Russians alongside the traditionally nomadic Kyrgyz majority, has long harboured the seeds for inter-communal unrest.

The interim government this week insisted that the situation was returning to normal, withdrawing a request for peacekeepers and insisting a constitutional referendum would be held as scheduled on June 27.

But the International Crisis Group warned that confident predictions that foreign intervention was not needed and the referendum could go ahead were “dangerously premature”.

“The situation in southern Kyrgyzstan remains unpredictable and volatile. A further upsurge of violence cannot be excluded. Neither can a spread of the unrest to other parts of the south.”

“The provisional government should request the assistance of the international community — through the United Nations Security Council,” it said.

It added the council should consider options to authorise the deployment of a limited law-enforcement mission or international military observer mission.

IHS Global Insight CIS political analyst Lilit Gevorgyan said the interim government was failing to maintain order “even in the ranks of police and army units”.

“Given the apparent inability of the provisional government to quell the conflict, international intervention may be the only option,” she said.