U.S. President Joe Biden warned Chinese leader Xi Jinping on Monday that a North Korean nuclear test would force Washington to take defensive countermeasures, even if it means being “more up in the face of China.”

The two leaders met in Indonesia ahead of the G-20 Heads of State and Government Summit, and after their meeting, Biden said he impressed upon Xi that Beijing has an “obligation” to try to dissuade Pyongyang from conducting nuclear tests.