WASHINGTON -- US Secretary of State Mike Pompeo has thanked South Korean Foreign Minister Kang Kyung-wha for Seoul's close cooperation on COVID-19 and reaffirmed the strength of the bilateral alliance, the State Department said Wednesday.

Pompeo and Kang spoke by phone on Tuesday to discuss the two countries' response to the coronavirus pandemic, according to a readout from the department.

"Secretary Pompeo thanked Foreign Minister Kang for the close cooperation and information sharing on COVID-19 and reaffirmed the strength of the US-ROK alliance, which continues to be the linchpin of peace and security in the Indo-Pacific and around the globe," it said, referring to the Republic of Korea, South Korea's official name.

Seoul's foreign ministry issued a similar statement after the call.

A ministry official who spoke on condition of anonymity added that the top diplomats addressed the issue of the stalled negotiations on defense cost-sharing.

While they agreed that the two sides should work to quickly reach a deal, there was no breakthrough toward a deal, the official said.

On Tuesday, Marc Knapper, deputy assistant secretary of state for Korea and Japan, reaffirmed that Washington expects Seoul to show "flexibility" in their talks.

The US has demanded significant increases in South Korea's contributions to the cost of stationing 28,500 American troops on the peninsula.

US President Donald Trump said last month that he had rejected a South Korean proposal because he felt it was not enough.

An earlier news report said Trump rejected Seoul's offer to increase its contribution by 13 percent from the $870 million it agreed to pay under last year's cost-sharing deal. (Yonhap)