International concern is mounting over the plight of those who have been pushed by the Tutsi-dominated army into camps in Bujumbura Rural province to clear the countryside for counterattacks against rebel forces.

Altogether more than 200,000 people have been "regrouped", most of them Hutus, who represent some 85% of the total population.

The BBC's Chris Simpson in Bujumbura:The coming rainy season will complicate the relief effort

UN relief agencies have so far visited 14 of 35 camps and found they lacked food, water, shelter and sanitation.

Diarrhoea and measles are spreading and there are signs of malnutrition in children.

A military spokesman in Burundi said the government had moved thousands of people from the camps to what he called protected villages where he said conditions would be better.

"The people asked for protection, and the only way we could protect them is to group them together," said Lt. Col. Longin Minani.

He said the move would enable people to continue farming instead of remaining idle.

The army says moving people to camps will help it track down Hutu rebels who in recent months have stepped up their attacks around the capital, Bujumbura.

It says it is simply trying to protect the civilians from the violence or from getting caught in crossfire.

But correspondents say it is widely believed that the real motive is to prevent them from feeding or sheltering the rebels.

EU statement

The upsurge in tensions has prompted 4,000 people to flee into western Tanzania in the past two weeks, said Kris Janowski, a spokesman for the UN High Commissioner for Refugees.

The US State Department and the European Union have echoed UN concerns.

A statement by Finland, which currently holds the UN presidency, said the EU "deplores the human rights violations, the loss of human lives and the destruction of property that accompanied the relocation operation".

Since Tutsi paratroopers assassinated the country's first democratically elected president, a Hutu, in 1993, more than 200,000 people, mainly Hutu civilians, have been killed in fighting between the Tutsi-dominated army and Hutu rebels.