China has tightened quarantine controls at its border with reclusive North Korea and barred the entry of poultry to prevent the spread of bird flu.

North Korea said on Sunday it had culled hundreds of thousands of birds after Avian Influenza hit two farms in Pyongyang, but did not say whether the bird flu virus was the H5N1 strain, which can jump from birds to humans.

China had strengthened border quarantine controls and no North Korean poultry or poultry products will be allowed to enter, the Agriculture Ministry said on its Web site, http://www.agri.gov.vn.

“The live poultry and relevant products trade at the border market is prohibited, and border residents are prohibited from bringing poultry with them when they enter China visiting friends or relatives,” said the ministry.

The three northeastern provinces of Heilongjiang, Liaoning and Jilin, historically known in the west as Manchuria and which border North Korea, also stepped up the fight against poultry smuggling.

China has not detected any cases of bird flu so far, it said, adding that all poultry along the border had been vaccinated.

Foreign Ministry spokesman Liu Jianchao said on Thursday that the border with North Korea was operating as usual.

South Korea, which has also stepped up quarantine measures at border points and at poultry farms near the border, believes the outbreaks in North Korea are extensive.

The H5N1 strain of bird flu has killed 34 Vietnamese, 12 Thais and 1 Cambodian since it swept across large parts of Asia in late 2003.