The White House says the U.S. remains concerned about a possible nuclear test and ballistic missile launches by North Korea.

During a press briefing on Thursday, U.S. National Security Advisor Jake Sullivan reiterated Washington’s concern in response to a question about whether the North could conduct a nuclear test during the Group of 20 summit set for next week in Indonesia.

Sullivan said the U.S. has been very transparent about its concern that the North could conduct its seventh nuclear test at some point in the broader timeframe, a possibility the U.S. has talked about for months, and the concern is still real as the “window still remains open.”

The official said that Washington is also concerned about further long-range missile tests in addition to the possibility of a nuclear test.

Sullivan said that the U.S. will be watching carefully for both forms of provocation, but their timing cannot be predicted.

Meanwhile, according to a U.S. National Security Council official on Thursday, North Korea will be on the agenda when President Joe Biden and Chinese President Xi Jinping meet for their first face-to-face summit on the sidelines of the G20 summit on Monday.