The assassination of Kim Jong Un's older half-brother at an airport in Malaysia has placed China on alert, and Beijing has deployed more troops at its border with North Korea "in case of a contingency."
Chinese foreign ministry spokesman Geng Shuang told reporters at a regular press briefing on Wednesday that his government is "paying attention to reports" regarding the slaying of Kim Jong Nam, South Korean news agency Yonhap reported.
"We are very interested in the progress of the case," the spokesman said, while adding that he cannot confirm whether Kim's family resides in Macau, a special administrative region of China.
Kim Jong Nam, who was 45, is believed to have had two families in China, according to Seoul's national intelligence service. His first wife and their son live in Beijing, while a second spouse lives with two children, a son and a daughter, in Macau.
China fears instability at its shared border with North Korea. If North Korea becomes "unstable" then hordes of them try to flee across the border to China.
The news may be behind a Beijing decision to increase the number of troops at the border, according to the Information Center for Human Rights and Democracy, a nongovernmental organization in Hong Kong.
Hong Kong newspaper Oriental Daily News reported China has deployed 1,000 additional troops to the area, and that local residents have confirmed their arrival.
Beijing has not issued a statement on the latest military movements.
Malaysia police arrested a woman with a Vietnamese passport in connection to the assassination, Yonhap reported Wednesday.
A woman captured on airport camera footage was identified as 28-year-oold Doan Thi Huong, but police are investigating whether the suspect is a Vietnamese national.
A Malaysia police source told Yonhap local authorities are tracking other suspects, including four men and one other woman who is believed to have been at the scene of the crime.
South Korean networks have reported Kim was fatally poisoned.