Antony Blinken. (Kyodo)  

U.S. Secretary of State Antony Blinken tested positive for the novel coronavirus on Wednesday, but is experiencing only mild symptoms and has not been in close contact with President Joe Biden, according to the U.S. government.

Blinken was planning to deliver a speech on Thursday that would outline the administration's policy toward China, but the schedule has been postponed.

The top U.S. diplomat's contraction of COVID-19 was the latest in a series of cases confirmed among White House officials, Cabinet members and lawmakers. Vice President Kamala Harris was also recently infected.

Blinken tested negative on Tuesday and Wednesday morning. But he tested positive in the afternoon via a PCR test. He is fully vaccinated and boosted against the virus, the State Department said.

Blinken met with Japan's national security adviser Takeo Akiba in Washington on Tuesday.