Three customs officers were injured on Thursday in a knife attack during an anti-narcotics raid in To Kwa Wan.

Authorities are looking for the suspect.

The incident happened shortly before 5pm when a team of seven customs officers were conducting an anti-narcotics operation at a flat in Honour Building on To Kwa Wan Road.

Of the three hurt, one has since been discharged.

The other two were treated for injuries on their limbs and were in stable condition.

Customs chief Chan Tsz-tat visited the injured officers at Queen Elizabeth Hospital.

"When our officers attempted to arrest the suspect, the suspect launched an attack," he told reporters.

"We strongly condemned the suspect. We would cooperate fully with the police force to bring the suspect to justice."

Chan said customs officers were well-equipped when carrying out such high-risk operations.

"Our officers are very professional and well-trained. They are also experienced in responding to similar cases," the customs commissioner said.

"We will continue to strengthen training for our officers in the future, including on self-defence and safety measures during such operations."

In a social media post, security minister Chris Tang also condemned the incident, saying law enforcement officers would do their best to try to catch the suspect.