Washington DC - President Donald Trump reportedly urged Tokyo to avoid provoking China over Taiwan when he spoke with Japanese Prime Minister Sanae Takaichi earlier this week.

According to a report from the Wall Street Journal, Trump spoke with Takaichi shortly after his call with Chinese President Xi Jinping on Monday and asked her to take the temperature down.

The row between Asia's two biggest economies began after Takaichi threatened China with military intervention if Beijing attacked Taiwan.

Beijing responded furiously, warning Chinese citizens against travelling to Japan and vowing to "crush" any foreign efforts to defend Taiwan.

During Trump's call with Xi on Monday, the Chinese leader pressed the issue, declaring Taiwan's return was an "integral part of the post-war international order."

Citing Japanese and American officials, the WSJ reported that shortly after that, Trump subtly told her to avoid the subject of Taiwanese sovereignty.

Japan on Thursday rejected the WSJ report and said that Trump had made no such request of Takaichi.

"The article has a passage that says, on the question of Taiwan's sovereignty, [Trump] advised [Takaichi] not to provoke the Chinese government. There is no such fact," government spokesperson Minoru Kihara told a regular media briefing, without elaborating.

Takaichi herself had briefly addressed the call shortly after it was made, telling reporters in Tokyo that she and Trump had "exchanged a wide range of views" which touched on China.

"President Trump said we are very close friends, and he offered that I should feel free to call him anytime," she claimed.