US Defense Secretary Lloyd Austin who arrived in Seoul on Monday for security talks with his South Korean counterpart Lee Jong-sup, has vowed that Washington is committed to protecting its East Asian ally in the event of a threat, local media reported on Tuesday.

Austin, said if an adversary challenges Seoul or Washington, it is challenging the two countries’ “alliance as a whole,” reaffirming the US’ “ironclad” security commitment to the Asian ally, Yonhap News Agency reported.

He was referring to North Korea as tension grew between Pyongyang and Seoul following missiles launches and military drills last year.

“This commitment includes U.S. conventional, nuclear and missile-defense capabilities, as well as the forward presence of 28,500 U.S. uniformed personnel (in Korea),” Austin was quoted as saying by the news agency.

“I am also here to reaffirm that the U.S. extended deterrence commitment to the ROK is ironclad,” he wrote in a piece published by the agency.

South Korean President Yoon Suk-yeol stated earlier this month that Seoul and Washington are discussing jointly implementing plans, including US nuclear assets, to respond to North Korean threats.

“South Korea and the United States are in talks over information-sharing, joint planning and the joint implementation plans that follow, in relation to the operation of US nuclear assets, to respond to North Korea’s nuclear weapons,” said Kim Eun-hye, senior presidential secretary for press affairs, according to Yonhap.

Tensions on the Korean Peninsula have risen again, with North Korea launching dozens of missiles in a series of weapons tests last year, including intercontinental ballistic missiles.