China and the U.S. aim to work more closely together in light of the spread of the coronavirus, leaders of both countries said in a phone call Friday Beijing time.

U.S. President Donald Trump said in a tweet that he spoke with his Chinese counterpart Xi Jinping “in great detail” about the COVID-19 pandemic, which has so far killed more than 24,000 people globally. The U.S. overtook China overnight as the country with the most confirmed virus cases, data showed.

“China has been through much & has developed a strong understanding of the Virus,” Trump said on Twitter. “We are working closely together. Much respect!”

The phone conversation followed a video conference meeting of G-20 leaders during which Xi gave a speech calling for greater international cooperation. The virus was first reported in late December in the Chinese city of Wuhan and has since killed more than 3,200 people in the country. The spread of the virus domestically has since stalled, but China has stepped up efforts to prevent travelers bringing the disease back from overseas by essentially closing borders to foreigners beginning Saturday.

In the call with Trump, Xi said that U.S.-China relations are at a critical juncture, and hoped the U.S. would make substantial action in improving the relationship, according to a Chinese-language state media report translated by CNBC.

“Under the current circumstances, China and the U.S. should unite to fight the epidemic,” the report of Xi’s comments said, noting both countries’ health departments and disease control experts have maintained communication.

“The Chinese side is willing to continue to provide information and experience with the U.S. without reservation,” the report added, noting some provinces, cities and businesses in China are providing the U.S. with medical supplies.

“The Chinese side understands the current difficulties of the U.S., and is willing to provide support within (China’s) ability.”

It was not immediately clear from the report whether China would give away supplies, or that it just hopes to sell more. China has donated some supplies externally since the crisis began, as well as accept assistance from outside.

Xi also emphasized that he hoped the U.S. would protect the health and lives of the many Chinese international students in the United States.

The phone call between the two leaders amid the global emergency follows almost two years of escalating trade tensions that were only partially resolved in January with the signing of a phase one trade agreement.

The Chinese state media report of the call noted Trump said China’s experience gave him “great inspiration,” and that America would protect Chinese citizens in the U.S., including international students.