South Korean President Yoon Suk Yeol will visit the US next week for a meeting with President Joe Biden as the allies try to figure out how to deal with North Korea’s increasing nuclear and missile capabilities.

Yoon’s visit will be the first by a South Korean leader to the United States since 2011, and it will coincide with the 70th anniversary of the nations’ connections.

The two leaders are expected to discuss joint responses to deter North Korea, partnerships to build more stable supply chains and expanding cooperation on chips, batteries and other high-tech areas.

“It will be an opportunity to further solidify the combined defence posture and operate extended deterrence between the two countries in a more concrete manner, while deepening economic security cooperation,” deputy national security adviser, Kim Tae-hyo, told a briefing.

Tension has flared on the Korean peninsula since the conservative Yoon took office in May last year, replacing a liberal president who had tried to promote negotiations with North Korea.

North Korea has ramped up the development of weapons, testing its first solid-fuel intercontinental ballistic missile last week, the latest in a series of tests.

North Korea says it needs its weapons to protect itself from plans by South Korea and the U.S. for “regime change”. South Korea and the United States deny any such intention.

Yoon has been pushing to boost South Korea’s role in operating what is known as U.S. extended deterrence, the American nuclear umbrella protecting its allies.

Yoon and Biden are also likely to consult on how to support Ukraine, amid mounting Western pressure for South Korea to help it battle Russian forces.

South Korea, a major producer of artillery ammunition, has tried to avoid antagonizing Russia, due largely to commercial interests and Russian influence over North Korea, focusing instead on humanitarian and financial aid for Ukraine.

In an interview with Reuters on Tuesday, Yoon hinted for the first time that his government might not “insist only on humanitarian or financial support” in the event of a large-scale attack on civilians or a “situation the international community cannot condone.”

Yoon will attend a summit and a joint press conference with Biden on April 26 and will make a speech to the United States Congress on April 27 before traveling to Boston to speak at the Harvard Kennedy School, according to Kim.