Police are stepping up the hunt for a six-month-old girl abducted outside a park in Kowloon City on Saturday night. Officers from the tactical unit were seen combing the area for clues yesterday afternoon, while plain-clothes detectives from the serious crime unit went door to door, speaking to shopkeepers and neighbours. "We have released photos and preliminary information to our frontline colleagues and we are trying our best to find her," said Chief Inspector Law Kwok-hoi of the New Territories North crime unit. Police are treating the case as kidnapping, and there are concerns the child could be smuggled to the mainland. Police say that at about 7.30pm on Saturday, the mother was pushing her baby in a stroller along Carpenter Road, opposite Carpenter Road Park and towards Kowloon City Plaza. A woman, whom police believe may have been working with the kidnapper, approached the mother and asked for directions to the Wong Tai Sin MTR station. After giving directions, the mother realised her baby had been taken from the stroller. She recalled that another person had walked past her very quickly while she was looking the other way to give directions. The woman seeking directions spoke with a thick mainland accent, police said. She was wearing a black top and blue jeans. A police statement last night gave more details, saying the woman was between 40 and 50, about 1.6 metres tall and of medium build. Frontline officers in New Territories North have been placed on high alert and border officials have been asked to keep a close eye on travellers with babies. Carpenter Road Park is a popular spot for families with young children. Bun Leung, a Kowloon City resident and new parent, said he was worried but would not be put off visiting the park. "I think parents should always keep their strollers placed in a direction where they can see it at all times. They should also keep the stroller seatbelts fastened." Chief Executive Leung Chun-ying described the case as "heartbreaking" when he spoke at a forum in Sha Tin yesterday. But he rejected criticism from a forum participant that he should have sent police keeping order outside the event to help with the investigation instead. Police said they were highly concerned about the case and asked any witnesses to call 6148 0919 or 6148 0920. A Facebook campaign launched on Saturday to raise awareness of the kidnapping case had amassed 36,000 supporters as of yesterday. Appeals were also seen on some mainland websites.