Discipline watchdogs in Chongqing City are investigating a senior city government official after he was reported to be seen having sex with his mistress in a set of pornographic pictures and videos widely spread online.

Lei Zhengfu?was reported to be seen having sex with his mistress in a set of pornographic pictures and videos widely spread online.

Lei Zhengfu, secretary of Beibei District Committee of the Communist Party in Chongqing, was accused by an investigative reporter with Southern Metropolis Daily of keeping an 18-year-old mistress and ordering police to detain her for over a month after the sexual images were leaked onto the Internet.

Lei denied the accusations, telling a reporter with China News Agency yesterday that the images are not real.

"Do not believe it. They are all fake," Lei told the reporter, "Just leave it (the case) alone."

Southern Metropolis Daily reporter Ji Xuguang said on his microblog yesterday that his information, from an unnamed source, indicated that Lei's mistress, Zhao Xiaoxue, secretly filmed sex videos and pictures after they quarreled.

"Lei then ordered police to catch his mistress and detain her for over one month," Ji alleged on his microblog.

Ji said on his microblog that in a telephone interview, Lei denied that he was the man in the pictures and said he never ordered police to detain a woman called Zhao Xiaoxue.

Discipline watchdogs said they are looking into whether Lei is the man in the sex pictures and videos. Investigation results are expected soon.