Hong Kong police have arrested a man suspected of hurling acid on people at a  crowded market in one of the city's famous tourist spots, officials have said.

At least 30 people were injured on Saturday night in the city's latest acid attack.

At least nine tourists and a seven-year-old child were among those injured. All the victims have been treated at local hospitals for burns and released.

The liquid was thrown on them near Temple Street, a densely populated district known for its outdoor shops and restaurants in the city's Kowloon area.

The suspect, who was described as a Chinese man in his 30s, was arrested after authorities found him on the roof of a nearby building along with the bottles believed to have been used in the attack.

Michelle Mak, a police spokeswoman, said that the suspect had not been formally charged, and the investigation is ongoing, but she did not say if the man was also suspected in other similar incidents that have terrorised the city.

Donald Tsang, the chief executive of Hong Kong, said authorities were offering a reward of $39,000 for information on the case.

The attack "makes people very angry and sad," Tsang told reporters on Sunday.

Police would not say if the man taken into custody was connected to five previous acid attacks in Hong Kong since December 2008 that have injured more than 100 people. 

Source: Al Jazeera and agencies