This file photo shows Pete Hegseth walking to an elevator for a meeting with President-elect Donald Trump at Trump Tower in New York on Dec. 15, 2016. (Getty Images)

US President-elect Donald Trump tapped Fox News Channel host Pete Hegseth to serve as his defense secretary on Tuesday, describing him as a "warrior for the troops and for the country."

Trump issued a statement on the designation of Hegseth, an Army veteran with tours in Guantanamo Bay, Iraq, and Afghanistan, as America's next defense secretary, who is tasked with handling a series of tough security challenges, including North Korea's military threats, Russia's war in Ukraine, and instability in the Middle East.

The Pentagon chief post requires Senate confirmation.

"I am honored to announce that I have nominated Pete Hegseth to serve in my Cabinet as The Secretary of Defense. Pete has spent his entire life as a Warrior for the Troops, and for the Country," Trump said.

"Pete is tough, smart and a true believer in America First. With Pete at the helm, America's enemies are on notice -- Our Military will be Great Again, and America will Never Back Down," he added.

Noting that Hegseth has led two veterans advocacy organizations, Trump said that "nobody fights harder for the troops."

"Pete will be a courageous and patriotic champion of our 'Peace through Strength' policy," the president-elect said.

South Korea has been keenly watching the designation of the US defense chief amid questions over whether the second Trump administration will continue strengthening joint deterrence efforts to counter North Korea's nuclear and missile threats, including the work of the Nuclear Consultative Group (NCG), a key nuclear deterrence body between Seoul and Washington.

Under the current Biden administration, Seoul and Washington have made strides in reinforcing the credibility of America's extended deterrence commitment to using the full range of its military capabilities, including nuclear arms, to defend its Asian ally.

But given Trump's perceived transactional approach to alliances, it remains uncertain whether Trump would inherit deterrence policy programs launched under the Biden administration, including the NCG and trilateral security cooperation with Japan.

Hegseth is the author of the recent book titled *The War on Warriors,* which Trump said reveals "how we must return our Military to meritocracy, lethality, accountability, and excellence."

He has been a host at Fox News for eight years. He is a graduate of Princeton University and has a graduate degree from Harvard University. (Yonhap)