SHANGHAI, Aug 4 -- POLICE are warning students to take extra care after a sudden surge in thefts from campuses last month.

There were 55 campus thefts throughout the city in July, a rise of 31 percent compared with the same period last year, the Shanghai Public Security Bureau said yesterday.

Most of the thefts occurred from 11am to 1pm or in the early hours of the morning. About 70 percent of the crimes took place at suburban primary and middle schools and vocational schools for adults.

Bureau official Zhang Jiaying yesterday warned people to be more careful and cited three recent cases.

A college librarian surnamed Zhang arrived at work on the morning of July 4 and reported to the police that a window in her office had been smashed and three computers and a digital camera that had been left on desks were missing.

That same morning an undergraduate surnamed Qiu also reported a burglary at his dormitory. This thief got away with a cell phone and 500 yuan (US$65) that he had left on his desk. His classmate neighbor also lost 800 yuan from his desk.

On July 5 a bolder thief struck at a university girls' dormitory. This woman stopped a girl surnamed Jin and told her she worked for television and was looking for an actress for a show.

"She told Jin that she looked perfect for the role and asked if she could take some photos," Zhang said. "So Jin took her to her dormitory and went into the bathroom to put some makeup on."

But when Jin came out of the bathroom looking beautiful, the brazen thief had vanished along with a laptop, two bottles of perfume, a dress and 800 yuan.

A school friend in the same dormitory also lost a laptop.

"Jin told police the woman had asked to borrow a large bag before she went to the bathroom."

The bureau warned schools to organize special staff patrols during the summer holidays.