SEOUL, South Korea (AP) — U.S. Vice President Kamala Harris is capping her four-day trip to Asia with a stop at the heavily fortified Demilitarized Zone dividing the Korean Peninsula as she tries to demonstrate the U.S. commitment to the security of its Asian allies.

The visit on Thursday comes on the heels of North Korea’s latest missile launches and amid fears that it may conduct a nuclear test. Visiting the DMZ has become something of a ritual for American leaders hoping to show their resolve to stand firm against aggression.

North Korea fired two short-range ballistic missiles on Wednesday, while Harris was in Japan, and had fired one before she left Washington on Sunday. The launches contribute to a record level of missile testing this year.

Before going to the DMZ, Harris met with South Korean President Yoon Suk Yeol at his office in Seoul and praised the alliance between the countries as a “linchpin of security and prosperity.” Yoon, a conservative who took office in May, called her visit “another turning point” in strengthening ties.

Harris and Yoon were expected to discuss the growing North Korean nuclear threats and the U.S. commitments to defend the South. They were also expected to discuss expanding economic and technology partnerships and repairing recently strained ties between Seoul and Tokyo to strengthen their trilateral cooperation with Washington in the region.

There are indications that North Korea may up the ante in its weapons demonstrations soon as it attempts to pressure Washington to accept the idea of the North as a nuclear power. South Korean officials said last week that they detected signs North Korea was preparing to test a ballistic missile system designed to be fired from submarines.

The U.S. aircraft carrier USS Ronald Reagan was to train with South Korean and Japanese warships in waters near the Korean Peninsula on Friday in the countries’ first trilateral anti-submarine exercises since 2017 to counter North Korean submarine threats, South Korea’s navy said Thursday.

U.S. and South Korean officials also say North Korea is possibly gearing up for its first nuclear test since 2017. That test could come after China holds its Communist Party convention on Oct. 16 but before the United States holds its midterm elections on Nov. 8, according to South Korean lawmakers who attended a closed-door briefing from the National Intelligence Service.