South Korean Foreign Minister Cho Hyun (L) and U.S. Secretary of State Marco Rubio spoke Monday about issues including North Korea. In this photo, the two diplomats shake hands before talks at the State Department in February. File Pool Photo by Yonhap/EPA

SEOUL, Aug. 25 (UPI) -- South Korean Foreign Minister Cho Hyun and U.S. Secretary of State Marco Rubio pledged to maintain close coordination on North Korea and other key issues in a phone call late Monday, Seoul's Foreign Ministry said, amid signs of strain between the allies over military exercises, Iran and trade.

The conversation came after U.S. President Donald Trump last week abruptly ordered the allies to curtail their annual Ulchi Freedom Shield military exercise, citing its cost and saying the drills sent an "inappropriate and hostile" signal to Pyongyang.

Cho and Rubio "agreed to continue close communication and coordination between the two countries for peace on the Korean Peninsula and the resolution of the North Korean nuclear issue, while maintaining a solid South Korea-U.S. combined defense posture," Seoul's Foreign Ministry said in a readout.

Cho said the South Korean government would "do its utmost to ensure that President Trump's recent message leads to the resumption of North Korea-U.S. dialogue and peace on the Korean Peninsula."