HANOI -- Vietnam has detected bird flu in chicken smuggled from China as the illegal trade picks up ahead of the lunar New Year later this month, state media reported Tuesday.

Eight out of 16 poultry samples tested by animal health officials in the northern border province of Lang Son were infected with the deadly H5N1 strain of avian influenza, said the Lao Dong (Labour) newspaper.

The provincial people's committee has sent an urgent message to local authorities, asking them to crack down on poultry smuggling to prevent the spread of infected poultry, the state-controlled newspaper said.

Animal health officials could not immediately be reached for comment.

Both China and Vietnam last week reported their first human cases of bird flu since early 2008.

Both countries in two weeks celebrate the traditional lunar New Year, called Tet in Vietnam, a time when the trade and consumption of chicken and other poultry usually rise sharply for large family feasts.

In Hanoi, food inspectors have discovered the widespread use of counterfeit quality stamps for poultry to disguise the origin of chicken from China, the state-run Vietnam News daily reported Tuesday.

Northern Vietnam has been gripped by winter weather recently, further raising the bird flu risk because the virus survives longer in the cold and people spend more time indoors, raising the risk of flu transmissions.

Vietnam has recently reported bird flu outbreaks among poultry in northern Thanh Hoa and Thai Nguyen provinces.

The communist government last week reported that an eight-year-old girl from Thanh Hoa province fell ill with bird flu after her family prepared and ate infected poultry. The girl is recovering, health officials said.

Her 13-year-old sister earlier died in hospital but was not tested for H5N1 before she was buried, health officials said.

In 2008, bird flu killed five people in Vietnam, raising the death toll there to 52, the second highest after Indonesia with 113 fatalities.

According to the World Health Organization, the number of human cases of bird flu worldwide since 2003 has reached 393 of whom 248 have died.

Bird flu mainly kills animals, but scientists fear it could mutate to jump easily from human to human, potentially sparking a global pandemic.