BEIJING -- The Chinese official who had accused the U.S. military of bringing the novel coronavirus to Wuhan walked back his statement on Tuesday, saying he was only trying to get back at American politicians stigmatizing China.

Foreign Ministry spokesman Zhao Lijian held a news conference for the first time in roughly a month, after tweeting on March 12 that it "might be U.S. Army who brought the epidemic to Wuhan."

His tweet was reported widely by Western media, and his long absence triggered speculation that he had been demoted over the comment.

Zhao stressed on Tuesday that "the virus was a scientific question that requires scientific opinions." He also called for greater cooperation between China and the U.S. in responding to the virus.

When asked if his tweet represents the view of the Chinese government, Zhao said "The questions raised on my personal Twitter account are a response to US politicians' stigmatization of China, which also reflects the righteous anger of many Chinese people over these stigmatizing acts."

Chinese President Xi Jinping is working to win over the international community through so-called mask diplomacy, sending medical supplies to the U.S., Europe, Japan, and other areas.

Zhao's offer for cooperation could also be an attempt to flaunt the Chinese Communist Party's handle on the situation.

Meanwhile, U.S. President Donald Trump is struggling to contain the coronavirus outbreak in his country. The president has been criticized at home and abroad for calling the coronavirus "the China virus," though he claimed the label is not racist.

Zhao's comments had triggered strong pushback from both countries. U.S. Secretary of State Mike Pompeo told top Chinese diplomat Yang Jiechi that "this is not the time to spread disinformation and outlandish rumors, but rather a time for all nations to come together to fight this common threat."

Chinese Ambassador to the U.S. Cui Tiankai also dismissed the claim as a "crazy" theory.