China tells travellers to use caution after 'malicious' US border checks

China advised its citizens on Thursday to use caution when travelling to the United States and avoid entry at Seattle's main airport following "malicious" border checks.

Around 20 Chinese scholars planning to attend academic conferences were "recently" denied entry by US Customs and Border Protection (CBP) at Seattle-Tacoma International Airport, despite holding valid visas, according to a foreign ministry statement.

CBP did not respond immediately to AFP's request, sent outside US business hours, for more information about the alleged entry denials.

The Chinese foreign ministry said that, "in light of recurring instances of malicious interrogation and harassment targeting Chinese scholars" at the Seattle airport, authorities "advise individuals planning to travel to the United States in the near future to heighten their safety awareness".

Chinese travellers should "avoid entry through this airport", it said.

The statement advised travellers to respond in a "calm and rational manner" if they were questioned by US border authorities.

The warning comes ahead of a planned mid-May visit to Beijing by US President Donald Trump, which was delayed for several weeks while Washington grapples with the war in the Middle East.