TIANJIN - Police in North China's Tianjin municipality confirmed that 20 rare birds were found dead and another 13 poisoned in the city's wetlands tainted by highly-toxic pesticide.

The birds that have been poisoned are not in life-threatening conditions, police added.

The birds, Oriental white storks, stopped at the city's Beidagang Wetland Nature Reserve along their migratory route when they were poisoned by the wetland water, media reports said Sunday.

Police said the water was confirmed to have contained carbofuran, also known as furadan, one of the most toxic carbamate pesticides, according to the Beijing News.

The remains and poisoned birds were discovered after an amateur photographer found the dead body of a stork on Nov 11, and other kinds of birds have also been found dead.

Local authorities are diluting the tainted water and looking for the sources of the pesticide.

The Oriental white stork is listed under China's highest level of animal protection, as only 2,500 to 3,000 of them currently exist in the country.

The species, which usually reproduces in the northeast, migrate south for winter, and the Beidagang Wetland is an important habitat along their migratory route.