China's Foreign Ministry said it is "verifying" claims that 77 Chinese children went missing from a home in Britain, allegedly sold to work in the prostitution and drugs trade.

British newspaper The Guardian, citing a secret immigration document on Tuesday, said at least 77 Chinese children had gone missing since March 2006 from the children's home, operated by the London borough of Hillingdon.

The anti-human trafficking office, under China's Ministry of Public Security, said on Friday that it has learnt of the case and Chinese police may take part in the investigation.

Chinese police have experience in taking joint action with other countries in cracking down on human trafficking, said the office. It has signed a memorandum of cooperation with its British counterparts, so if the trafficked children were Chinese citizens, the office can become involved.

The Guardian cited the "restricted" report as saying victims of a trafficking network, that has agents based as far apart as China, Brazil, Japan, Malaysia and Kenya, arrived at the home just outside the airport perimeter, only to disappear almost immediately.

China's embassy in London said on Friday it hoped the UK side could clarify the issue as soon as possible.

An embassy spokesman said China is opposed to human trafficking of all kinds.

Only four of the 77 children have been found, according to The Guardian. Two girls returned after a year of exploitation in brothels in the Midlands. Others, said the article, are coerced with physical threats to work as street-sellers of counterfeit goods. It is thought many also work on illegal cannabis farms.

UK Prime Minister Gordon Brown vowed on Wednesday to investigate the report.