The US military said that a Chinese fighter pilot flew aggressively last week near a US surveillance aircraft over the South China Sea, with Beijing blaming US "provocation" for the episode.

The Pentagon also said that China's Defence Minister Li Shangfu declined talks with US Defence Secretary Lloyd Austin when the two are in Singapore this week for the annual Shangri-La Dialogue.

Blinken said that US aeroplanes were "flying in international airspace on a routine mission".

"There have been a series of these actions directed not just at us but at other countries in recent months," Blinken told reporters on a visit to Sweden.

"I think it only underscores why it is so important that we have regular, open lines of communication including, by the way, between our defence ministers," Blinken said.

"The most dangerous thing is not to communicate and, as a result, to have a misunderstanding and miscommunication," Blinken said.

"And as we said repeatedly, while we have a real competition with China, we also want to make sure that doesn't veer into conflict and the most important starting point for that are regular lines of communication."

Blinken cancelled a trip to Beijing in February after the United States said it spotted a surveillance balloon from China over the US mainland.