South Korean President Park Geun-hye on Friday praised the country's decades-old alliance with the United States during a meeting with a senior U.S. lawmaker who voiced concerns over North Korea's threats to conduct another nuclear test and alleged progress in its nuclear and missile programs.

"The South Korea-U.S. alliance is referred to as one of the most successful alliances around the world and the state of our alliance has never been better," Park said in a meeting with a U.S. delegation led by Howard "Buck" McKeon, chairman of the House Armed Services Committee.

The meeting came a day after North Korea threatened to conduct a nuclear test and boasted that it has mastered the technology to make nuclear warheads small enough to fit on a ballistic missile capable of striking the U.S. mainland.

"As chairman of the House Armed Services Committee, one of my greatest worries is the threat posed by North Korea," McKeon said, without elaborating further.

On Thursday, North Korea's state news agency said in a commentary that the North "will take countermeasures for self-defense which will include missile launches and nuclear tests" in response to South Korea-U.S. joint military drills set to begin on Aug. 18.

The North has frequently condemned military exercises as a rehearsal for invasion of the North, a charge denied by Seoul and Washington.

South Korean officials have said North Korea -- which conducted nuclear tests in 2006, 2009 and 2013 -- is ready to conduct a fourth nuclear test at any time.

The commentary also said North Korea's strategic rockets tipped with nuclear warheads are powerful enough to strike the U.S. mainland, a claim that cannot be independently verified.

Outside experts doubt Pyongyang has mastered the miniaturization technology needed to mount a nuclear warhead on a ballistic missile.

(Yonhap)