As North Korea defied President Trump and carried out its sixth and most powerful nuclear test to date Sunday, Colorado Sens. Michael Bennet and Cory Gardner were tuned in and concerned with different takes on the serious threat to the mainland U.S.

Gardner, a Republican from Yuma is chairman of the subcommittee on East Asia, the Pacific and International Cybersecurity, said Sunday afternoon it’s time to take “unprecedented steps to stop North Korea.”

Trump was unclear Sunday about whether or how the U.S. might respond, though in the past he has said that revealing military strategy is counter-productive.

“The president must acknowledge the gravity of the situation, demonstrate leadership befitting of the office, and articulate a strategy to address this threat alongside our international partners,” Bennet, a Democrat from Denver, said in a statement Sunday afternoon.

Bennet has called for a comprehensive strategy to deal with North Korea, working with allies in the region. Trump accused the U.S.’s strongest ally there, South Korea, of appeasing of North Korea. The president has taken jabs at China over North Korea’s nuclear rise, as well.

The hydrogen bomb tested Sunday could be delivered to the mainland United States via a missile, which Gardner said is a clear signal that North Korea’s Kim Jong Un is girding for nuclear war, regardless of lives that would be lost.

“The international community needs to finally join together in completely isolating this dangerous regime,” Gardner said. “North Korea should be immediately kicked out of the United Nations and under the leadership of the United States, the United Nations Security Council should enact a new resolution that imposes a full economic embargo on North Korea that bans all of Pyongyang’s economic activities, including petroleum resources, except for limited humanitarian exceptions.”

Gardner’s office pointed to bipartisan legislation he introduced in July to ban any entity doing business with North Korea (“or its enablers”) from using the U.S. financial system.

“I am ready to work with the administration and leaders in Congress to pass this bill immediately,” Gardner said Sunday.

He said economic sanctions should be couple with a “robust” military response, including an international naval blockade of North Korea.

“We must also continue frequent show of force exercises by the United States and our partners in Seoul and Tokyo, enhanced missile defense activities, and assurance of extended U.S. nuclear deterrence to our allies,” Gardner said.

“Kim Jong Un must know that any serious provocation will be met with a full range of U.S. military capabilities.”