Bangladesh has culled about 13,000 chickens after fresh outbreak of bird flu in the country last month, officials said Monday.

Ataur Rahman, bird flu control room official, told Xinhua, a total of '12,789 chickens were culled so far this year after fresh outbreak of the avian influenza in commercial farms.'

Of the total, he said, '9,526 birds, including 8,821 in a commercial firm in Dhaka, were culled in the first week of this month.'

In January, when the outbreak of the disease was reported, 3,263 chickens were culled.

Habibur Rahman, director general of Bangladesh's Fisheries and Live Stock Department, said the department has strengthened its surveillance to contain further spread of the infectious disease.

So far, four districts were affected by bird flu.

Officials, however, said with the rise of temperature in March and April, the risks from the disease would gradually ease.

Bird flu was first detected in Bangladesh in a poultry farm near Dhaka in March 2007.

The disease was later spread to 47 districts between December 2007 and March 2008.