National Security Adviser H.R. McMaster said Tuesday that North Korea has continued “to perfect” its weapons program and called for swift action from the United States and its allies to block the regime from successfully completing its nuclear program.

The U.S. must “act urgently” to enforce existing sanctions and take further steps with regional allies like South Korea and Japan to convince North Korean dictator Kim Jong-un to abandon his weapons program, McMaster said in an interview with PBS NewsHour’s Judy Woodruff.

“As this regime continues to perfect its long range nuclear capabilities, it’s just a risk that the world cannot tolerate,” McMaster said.

“As this regime continues to perfect its long range nuclear capabilities, it’s just a risk that the world cannot tolerate,” McMaster said.

McMaster indicated that taking military action remains on the table. Earlier this year, President Donald Trump promised to bring “fire and fury” on North Korea if it took actions that threatened the U.S. and other countries.

North Korea has launched several missile tests since Trump took office, including launching an intercontinental ballistic missile last month that caused widespread concern in the region. North Korea claimed such a missile was capable of hitting the U.S.

“The president asked us to continue to refine a military option should we have to use it,” McMaster said, though he declined to go into specifics.

But McMaster called for a diplomatic solution to the crisis, urging Russia, Japan and other nations to work with the U.S. to avoid a military confrontation with North Korea.

The U.S. and its allies must “take all the diplomatic action, all the economic action we can to convince Kim Jong-un this is a dead end,” McMaster said.

McMaster’s comments came just hours after Trump outlined his national security strategy in a high-profile speech Monday.

Trump called for an America-first approach that prioritizes protecting Americans in the U.S. and abroad. Trump also mentioned fighting “rogue regimes” like North Korea and linked national security to economic security, arguing that the U.S. would do more to confront “economic aggression” from countries like China.

Watch Judy Woodruff’s full conversation with National Security Adviser H.R. McMaster here.