The Red Cross says several hundred people have died during recent riots in Kyrgyzstan, suggesting the death toll could be higher than what the government is claiming.

Riots in southern Kyrgyzstan broke out in recent days, targeting minority Uzbeks -- a group that largely supports the interim government that forced leader Kurmanbek Bakiyev from office during an uprising in April.

So far, at least 179 people have been killed and another 1,900 injured, according to figures released by the Kyrgyz government led by Interim President Roza Otunbayeva.

But the International Committee of the Red Cross believes "we are talking about several hundreds" of people who have been killed, spokesperson Christian Cardon said Tuesday.

Rioters have also burned down much of Osh, Kyrgyzstan's second-largest city, prompting 100,000 Uzbeks to seek asylum in neighbouring Uzbekistan.

There is growing suggestion that the riots in Kyrgyzstan may have been planned out in advance.

In Geneva, UN High Commission for Human Rights spokesperson Rupert Colville told reporters that five simultaneous attacks by masked men set off the rioting in Osh.

Navi Pillay, the UN High Commissioner for Human Rights, said the fighting in Kyrgyzstan "appears to be orchestrated, targeted and well-planned."

The interim Kyrgyz government accuses the ousted Bakiyev and his family of inciting the recent violence and trying to delay the fast-approaching June 27 referendum on a new constitution.

"Many instigators have been detained and they are giving evidence on Bakiyev's involvement in the events. No one has doubts that he is involved," Interim President Roza Otunbayeva said Tuesday.

The country's deputy security chief, Kubat Baibalov, said the attacks on Osh were started by a group of five men from Tajikistan, which borders parts of southern Kyrgyzstan.

Bakiyev, who is living in self-exile in Belarus, has denied having any part in the violence.

The former Kyrgyz leader's son, Maxim, was arrested in Britain on Monday, said Kyrgyz security chief Kenishbek Duishebayev.

The younger Bakiyev is suspected of skipping out on nearly $80 million of taxes he should have paid for aviation fuel he sold to suppliers of a U.S. military base in Kyrgyzstan.

Also Tuesday, the United Nations and the European Union called on Kyrgyzstan to stand tall in the face of recent violence and to hold the referendum and the upcoming October parliamentary elections as scheduled.

"The referendum and the elections must be held at the announced times," said UN representative Miroslav Jenca, stating a position that German ambassador Holger Green said was echoed by the EU.