MANILA, Philippines (AP) — South Korea and the Philippines, each faced by increasingly hostile rival nations, elevated their ties to a strategic partnership on Monday, including broader defense and security cooperation between the two U.S. treaty allies.

South Korean President Yoon Suk Yeol, who is on a state visit to the Philippines, and Philippine President Ferdinand Marcos Jr. announced the upgrade in overall relations after talks in Manila.

Under the strategic partnership, the two countries agreed to strengthen cooperation between their coast guards. Yoon also pledged to help modernize the Philippine military.

The two leaders discussed regional issues such as territorial disputes in the South China Sea and tensions on the Korean Peninsula, they said.

Marcos said in an opening statement that “as the geopolitical environment is only becoming more complex, we must work together to achieve prosperity for our peoples and to promote a rules-based order governed by international law.”

Philippine and Chinese coast guard vessels have clashed repeatedly in disputed waters in the South China Sea, with Chinese ships using water cannons and dangerous maneuvers in incidents that have injured several Filipino navy personnel and damaged supply boats.

Yoon stressed the importance of peace and stability in the South China Sea, and added that the two leaders “reaffirmed that the international community will never condone North Korea’s nuclear programs and its reckless provocations, as well as its illegitimate military cooperation with Russia.”

Yoon said North Korea’s recent disclosure of a nuclear facility was likely an attempt to grab U.S. attention ahead of next month’s American presidential election.

The Philippines is the first stop on a six-day Southeast Asia tour for Yoon which will also take him to Singapore and Laos, where he will attend a summit of the Association of Southeast Asian Nations.