A well-known Chinese columnist has gone missing after warning former colleagues of the danger of re-publishing an open letter calling for President Xi Jinping to resign, the journalist's lawyer said Thursday.

Jia Jia, who writes a regular column for Tencent Online, went missing late Tuesday, around the time he was scheduled to board a flight from Beijing to Hong Kong, his lawyer, Yan Xin, told Reuters.

Before his scheduled departure, Jia had told friends he believed something could happen to him after he had warned former colleagues about republishing the letter, Yan said.