China’s foreign ministry denounced White House trade adviser Peter Navarro as a “liar,” in the latest volley between the two sides over the coronavirus outbreak.

Foreign Ministry spokesman Geng Shuang on Tuesday repeated its past rejection of Navarro’s claims that the Chinese side had held back supplies of vital personal protective equipment amid the Covid-19 pandemic. “Navarro has been a consistent liar with no credibility,” Geng told a regular news briefing Tuesday in Beijing.

Navarro, who wrote “Death by China: Confronting the Dragon—a Global Call to Action” before joining the White House, has equated the dispute with China to “a war.” “It’s a war that China started by spawning the virus, by hiding the virus, by hoarding personal protective equipment during the time it hid the virus,” he said during an interview Saturday with Fox News.

Navarro has redoubled his criticism of China in the wake of the coronavirus, drawing increasingly sharp rebukes from Beijing. While Chinese officials have sometimes denounced U.S. officials, including Secretary of State Michael Pompeo, they have avoided outright criticism of President Donald Trump himself.

Navarro has argued that tariffs have spurred growth amid the ongoing trade war between the U.S. and China, which dominated headlines about the relationship between the world’s two biggest economies before the virus emerged late last year.

Trump last month appointed Navarro to coordinate actions under the Defense Production Act, a law that can quicken the production of items needed by hospitals during the pandemic. Navarro has said that the Trump administration had concerns about whether 3M Co.’s production around the world was being delivered to the U.S., as Trump attacked the company over concerns with supplies of protective face masks.