Assistant U.S. Secretary of State for East Asian and Pacific Affairs Daniel Kritenbrink speaks at a hearing with the Senate Foreign Relations Committee in Washington, D.C., Dec. 8, 2021. AFP-Yonhap

The United States has been left with no option but to "double down" on security cooperation with South Korea and Japan, and the enforcement of anti-North Korea sanctions due to the recalcitrant regime's rejection of dialogue, a senior U.S. diplomat said Tuesday.

Daniel Kritenbrink, assistant secretary of state for East Asian and Pacific affairs, made the remarks, underscoring that Washington is "certainly" focusing on North Korea that he cast as one of the "most significant" security challenges in the Indo-Pacific.

His remarks came as critics have raised election-year questions over President Joe Biden's approach towards North Korea amid little headway in U.S. efforts to reengage with Pyongyang despite the regime's dogged pursuit of advanced weapons programs and its military cooperation with Russia.

"I think we've had no choice but to double down on our security arrangements, particularly with the Republic of Korea and Japan, and no one should doubt the ironclad nature of our security commitments to those allies," he said during a forum hosted by the Washington-based Brookings Institution.

"We've also doubled down with a large international coalition of partners who continue to enforce sanctions against North Korea. I think given North Korea's unwillingness to respond to our offer of diplomacy, we've been left with no choice but to focus on these harder elements of our strategy."

Kritenbrink reiterated that Washington has pursued dialogue with the North "without preconditions" while highlighting its security commitment to its allies.

"Unfortunately, the only response we've received thus far from the DPRK has been more missile launches," he said. DPRK stands for the North's official name, the Democratic People's Republic of Korea.

Despite evolving North Korean threats, Kritenbrink pointed out progress in bilateral and trilateral efforts to counter the threats among Seoul, Washington and Tokyo.

"Our trilateral cooperation has also really reached unprecedented levels. And we have to be candid that a lot of that cooperation is designed to counter this growing threat from North Korea," he said.

He was referring to agreements from a landmark summit that South Korean President Yoon Suk Yeol, Biden and Japanese Prime Minister Fumio Kishida held at Camp David in Maryland in August. The summit agreements included the "Commitment to Consult" each other in the event of a shared threat.

"There are many challenges across the Indo-Pacific. This (North Korea) remains one of the most significant and we are certainly focused on it on a daily basis," he said. (Yonhap)

（作者：汽车音响）