South Korea is aware of news reports about a leak of several classified U.S. military documents and it plans to discuss "issues raised" as a result of the leak with the United States, a South Korean presidential official said on Sunday.

Several classified U.S. military documents have recently been posted on social media offering a partial, month-old snapshot of the conflict in Ukraine, three U.S. officials told Reuters on Friday.

The New York Times reported on Sunday that the leaked documents contain details about internal discussions among top South Korean officials about U.S. pressure on the staunch ally to help supply weapons to Ukraine, and its policy of not doing so.

The newspaper said that South Korea had agreed to sell artillery shells to help the United States replenish its stockpiles, insisting that the "end user" should be the U.S. military. But internally, top South Korean officials were worried that the United States would divert them to Ukraine.

"The secret report was based on signals intelligence, which meant that the United States has been spying on one of its major allies in Asia," the New York Times reported.

The South Korean presidential official, speaking to reporters, declined to respond to questions about U.S. spying or to confirm any details from the leaked documents.

Asked if South Korea planned to lodge a protest or demand an explanation from the United States, the official, who declined to be identified, said the government would review precedents and cases involving other countries.

South Korea has signed major deals providing hundreds of tanks, aircraft and other weapons to NATO member Poland since February last year. But President Yoon Suk-yeol has said a South Korean law that forbids supplying weapons to countries engaged in conflict makes it difficult to send arms to Ukraine.

The South Korean official said there was no change to South Korea's policy.

Yoon is scheduled to meet U.S. President Joe Biden on April 26 during a state visit to Washington.

What else do the documents say?

According to the New York Times and the Washington Post, the first tranche of documents appeared to have been posted in early March on Discord, a social media chat platform popular with video gamers.

On Wednesday, images showing some of the documents began circulating on the anonymous online message board 4chan and made their way to at least two mainstream social media platforms, Telegram and Twitter.

Information in the documents is at least five weeks old, with the most recent dated March 1.

The documents included precise details about the Ukrainian battlefield, use of U.S. weapons by Ukraine and the training of Ukrainian troops.

A new batch of classified documents leaked on Friday also detailed U.S. national security secrets from Ukraine to the Middle East to Asia.

CNN reported the topics of these leaked documents ranged from the Wagner Group's operations in Africa and Israel's pathways to providing lethal aid to Ukraine, to intelligence about the United Arab Emirates' ties to Russia and South Korean concerns about providing ammunition to the U.S. for use in Ukraine.

Iran's nuclear program and the Democratic People's Republic of Korea's missile program are also mentioned.

CNN cited an anonymous U.S. official who said these documents "look real."

As of Saturday, photographs of the documents were still being posted on various social media platforms.

(With input from agencies)

(Cover: South Korean President Yoon Suk-yeol speaks during a Cabinet meeting at the presidential office in Seoul on April 4, 2023. /CFP)