Two Spanish brothers, aged 10 and 11, have gone missing, prompting police to make a public appeal for help to find them.
Immigration records show that 10-year-old Miguel Rubio Hermansanz and his elder brother, Nicolas, left the city for Macau with their father on Monday morning, according to a police source.
Last night, police were investigating whether the boys and the man were still in Macau.
The source said that if necessary, the police would seek help from their counterparts in Macau to locate the boys.
The search began when the boys' mother reported them missing at about 5.15pm on Monday.
The 48-year-old woman, whom police identified only as Maria, told officers that she had last seen her two sons at home on Mount Davis Road, in Pok Fu Lam, at about 8.30am on Monday before she went to work.
A police investigator said the two brothers had disappeared after they left home at about 10am on Monday.
"Closed-circuit TV showed the two boys leaving the building on their own and no one picked them up," he said.
According to police, she said that under a court order, her ex-husband could not take the boys away without her permission. Police have identified the ex-husband only as David.
The brothers, who hold Spanish passports, study in Hong Kong and live with their mother, who works as a real estate consultant in Wan Chai.
Anyone with information should call the police on 3660 7410 or contact a police station.