President Yoon Suk Yeol doubled down on bolstering extended deterrence, a US pledge to use all resources including nuclear weapons to deter and respond to attacks on its allies, amid deepening Seoul-Washington ties to counter North Korea’s nuclear threats

The two allies are pursuing a more united front on Pyongyang, as they return to full-scale military exercises Monday following a five-year hiatus meant to give room for diplomacy on North Korea’s denuclearization. The efforts had yielded little headway.

“The drills will be scaled up to deliver on our ‘alliance in action,’” Yoon said Friday, addressing the graduating class of the country’s Naval Academy in Changwon, South Gyeongsang Province.

Yoon administration officials use the motto to highlight an alliance quick to safeguard interests concerning both South Korea and the US as they confront global challenges beyond North Korea, from dealing with economic disruptions to climate change. To mark 70 years of ties, Yoon will meet with US President Joe Biden in late April, South Korea’s first state visit hosted by its biggest ally in 12 years.

Closer Seoul-Washington ties have been the norm since at least May last year, when the conservative South Korean leader took over with a promise to bolster ties with not only the US but Japan. Tokyo is a partner in the Washington-led three-way coalition working on dismantling Pyongyang’s nuclear and missile programs.

“We can’t just rely on the goodwill of those we’re dealing with because that is ‘fake peace.' Real peace comes when we project power,” Yoon said, clearly indicating South Korea would not submit to North Korea’s demand that it halt field maneuvers with the US. Pyongyang has labeled them “rehearsals for invasion,” though the two allies say they are testing readiness.

A day earlier, North Korea fired off short-range ballistic missiles, the latest show of force following its warning issued Tuesday. Then Kim Yo-jong, the powerful sister of leader Kim Jong-un, said Pyongyang was ready to deliver “overwhelming blows” to anyone threatening the isolated country, which still defies United Nations Security Council resolutions banning ballistic missile tests.