More than a week after the Tianjin warehouse explosion that killed at least 114 people, large numbers of dead fish have washed ashore in the northern Chinese city, causing fresh public alarm and inciting fears of greater environmental damage linked to the chemical blast.

Photos of thousands of small dead fish on the shore of the Haihe River circulated widely on social media soon after they were published by Chinese state media late Thursday afternoon. One posting was forwarded more than 6,000 times and received 4,300 comments less than three hours after it was published.

A posting on Weibo showing dead fish washed ashore in Tianjin. Weibo.com

City environmental officials said late Thursday that they didn't find toxic levels of cyanide from the river during an analysis that afternoon, according to the official Xinhua News Agency. Deng Xiaowen, director of Tianjin’s environmental monitoring bureau, said at a press conference Thursday afternoon that experts were investigating the dead fish but that such incidents were "not rare" during the summer, the state-run China Daily newspaper reported.

The fish were found six kilometers away from the blast site, the paper said.

About 40 different chemicals were stored at the warehouse, including highly toxic sodium cyanide, according to Xinhua.

Photos and videos from the blast site have gone viral since the explosion last Wednesday, although China’s censors have been working overtime to keep control of the online discussion. The move to publish the photos, then, is something of an unexpected move by Chinese state media, which typically follows the authorities’ lead in downplaying the extent of natural disasters in the country.

Many Web users on Thursday responded with rage to the images.

“If the dead fish are related to the explosion, then this is a regional disaster,” one user wrote on Weibo. “The culprits must be sentenced to death.”

--Felicia Sonmez. Follow her on Twitter @feliciasonmez.

Note: This item has been updated to reflect Xinhua's report on the Thursday analysis of cyanide levels in the river.