A Hong Kong school principal has been suspended from his post with immediate effect after he was seen swearing at security guards during a student trip to Singapore, the institution announced on Tuesday, hours after authorities in the city state revealed they would investigate the incident.

Edmund Wong Chun-sek, a former lawmaker and manager of San Wui Commercial Society Secondary School in Tuen Mun, told the South China Morning Post that the decision was taken because the principal’s behaviour fell short of public expectations and the board wanted to demonstrate its resolve in handling the matter.

Wong said the management committee reached the decision after hearing evidence on Tuesday from principal Lee Cheuk-hing and staff who joined the trip.

The decision was made after Lee had left the meeting.

“Though he said he wanted to protect the students, his actions did not meet what the public expects of a school principal,” he said.

In response to queries from the SCMP, Singapore police said on Sunday evening that they had received a report and that investigations were under way.

Asked how the investigation could proceed given the suspect had already returned to Hong Kong, a spokesman for Singapore police said the relevant authorities were investigating the incident and might take appropriate action.