A United Nations human rights official has said the government crackdown on opposition protests following the Cambodian elections has raised fresh and serious concerns about the country's human rights environment.

Speaking at the end of a week-long visit to Phnom Penh, the UN Secretary General Special Representative for Human Rights in Cambodia, Thomas Hammarberg, said that at least 34 people had been killed in August and September.

Many of the bodies which were found in shallow ditches and rivers showed signs of execution-style killings, including broken limbs, bullet wounds and marks of strangulation.

18 monks needed medical treatment

However, Mr Hammarberg said that so far only two of the deaths occurred when the security forces intervened to break up opposition protests against allegations of electoral fraud.

But he said 24 other killings took place in the period which co-incided with the government crack-down on the demonstrations, although no direct link between the two could yet be established.

Nearly 80 other people, including 18 monks and a nun, needed medical treatment for injuries during the suppression of the protest, and scores of people were arrested or detained by the authorities - with about 50 people still reported missing.

Cautious welcome

Mr Hammarberg welcomed a request from government officials for help in trying to reform the country's legal and criminal systems.

Last week Prime Minister Hun Sen also publicly stated that he wanted to strengthen human rights work in Cambodia.

However, Mr Hammarberg said it was still difficult for those who wanted to voice opposition views and that much remained to be done.