North Korea has finished preparations for a nuclear test and only has to make a “political decision” to carry it out, South Korea’s foreign minister said Monday, warning that such a test will only further isolate Pyongyang from the international community.

Park Jin’s remarks came during a joint press briefing with U.S. Secretary of State Antony Blinken, who noted that the U.S. is ready to make “short and long-term adjustments” to its military posture as it prepares for “all contingencies.”