Authorities in Chuzhou, a city in East China's Anhui province, vowed on Wednesday to cooperate with the ongoing river pollution investigation.

The Chuhe River, a tributary of the Yangtze River, was polluted after a recent fire at a chemical repository in the city's Quanjiao county.

A Wednesday morning conference attended by the city's top officials warned against any cover-up of the investigation, which had been launched by the provincial authorities, according to Chuzhou Daily's report on Thursday.

The pollution led to mass fish deaths in the section of the river passing through Chuzhou and in its lower reaches in Nanjing, the capital of neighboring Jiangsu province, media outlets reported.

The conference requires taking measures, including damming the waters in the downstream of the burnt building to prevent further pollution.

The remaining polluted water must be treated before the arrival of the flooding season, which usually lasts from June to September.

The authorities also vowed to investigate related officials and the repository's legal responsibility.

The county's former Party secretary, environmental protection chief and another two officials had been removed from their positions prior to the conference, according to previous media reports.

Yu Chenglin, vice mayor of Chuzhou, had been appointed to serve concurrently as Party secretary of Quanjiao county.