In a separate case, about seven packs of green and white capsules were found discarded in a wheat field in Guodian township of Xinzheng city.

Samples have been sent to the pharmacy authority for further checks, said Du Changtao, an official from the publicity department of Zhengzhou.

The Ministry of Public Security announced on Sunday that it had confiscated 77 million tainted capsules in Zhejiang, Jiangxi and Hebei provinces, arrested nine suspects, detained 54 people and sealed 80 manufacturing lines.

Liu Aiguo, an employee of the Hebei Xueyang Glair Gelatin Factory, was detained by police on Saturday evening after allegedly setting fire to the plant on instructions from his superiors in a bid to destroy evidence, said the Ministry of Public Security.

The Ministry of Health on Saturday required hospitals nationwide to stop using contaminated medicine capsules, and said hospitals must sort through their inventories, and remove and seal any suspected contaminated medications.

The administration announced on Monday that it had revoked production licenses of another two gelatin-capsule manufacturers in Zhejiang province for "grave violations of laws and regulations". The licenses of three pharmacy companies in Zhejiang province were revoked on April 19.

The Beijing Drug Administration has recalled 12,000 packs of tainted capsules as of Monday, and the municipal government has tightened checks on local pharmaceutical manufacturing companies, the administration said on its website.

The Xiuzheng Pharmaceutical Group Company apologized to the public on its website on April 19 after the State Food and Drug Administration listed one of its products for cold treatment as being contaminated with chromium.

The company had halted the manufacturing line of the problematic capsule and withdrawn 199 batches of the listed capsules, said the company's statement.