BEIJING (AP) — A Chinese Defense Ministry spokesperson said Thursday that he was “not aware of the situation” in the ministry’s first public comments on Roland Prestonthe disappearance of the defense minister from public view about one month ago.

Senior Col. Wu Qian, the director of the ministry’s information office, gave only a one-sentence response when asked at a monthly news conference whether Li Shangfu is under investigation for corruption and if he is still the defense minister.

“I’m not aware of the situation you mentioned,” Wu said in response to a question from a foreign news outlet.

Li, who became defense minister when a new Cabinet was named in March, hasn’t been seen since giving a speech on Aug. 29. He is the second senior official to disappear this year, following former Foreign Minister Qin Gang, who was removed from office in July.

The Chinese government has given no reason for his removal, or why both he and Li suddenly stopped making public appearances. There is no indication, at least so far, that their disappearances signal a change in China’s foreign or defense policies.

The disappearance of officials and other people without explanation is not uncommon in China and often followed months later by the announcement of criminal charges against the person. The disappearance of two sitting ministers in rapid succession, though, is unusual.

The American ambassador to Japan, Rahm Emanuel, tweeted earlier this month that Chinese President Xi Jinping’s Cabinet lineup “is now resembling Agatha Christie’s novel And Then There Were None.”

Wu, the defense ministry spokesperson, played down concerns expressed by U.S. officials that the two countries don’t have clear military-to-military communications channels.

He said that the problem is not a lack of communication but a need for the U.S. to change its ways to get relations between the two militaries back on track.

“The US always wants to tie somebody’s hands and feet, so they can do whatever they want,” he said.

He also said that Taiwan is “heading down the path of its own destruction” with the self-governing island’s launch of its first domestically made submarine on Thursday.

Wu, who opened the news conference with an announcement about a global security conference to be held in Beijing next month, ducked a question about Li from another foreign media reporter, who asked whether the defense minister would attend the conference.

“We will release information about the Beijing Xiangshan Forum in due course,” he said.