BRASILIA -- The Chinese government was shocked by the crash of a Malaysian plane in Ukraine and determining whether there were Chinese citizens onboard, a foreign ministry spokesman said here Thursday.

"We are shocked by the news that the Malaysia Airlines MH17 flight crashed in eastern Ukraine. We convey our deep condolence to the victims and our sincere sympathy to their families," Qin Gang said in a statement.

"We hope that the causes can be found out as soon as possible," added Qin, who is accompanying Chinese President Xi Jinping in Brazil on a four-nation Latin America tour.

He said that the Chinese foreign ministry and relevant embassies have activated an emergency mechanism and are checking whether there were Chinese passengers.

"We will closely follow the incident, keep close contact with relevant parties and take corresponding measures," he said.

A Boeing 777 passenger plane of the Malaysia Airlines crashed in eastern Ukraine en route from Amsterdam to Kuala Lumpur earlier Thursday, with all 295 people onboard feared dead.

The Ukrainian government and rebels in the region accused each other of shooting down the plane.