The former top cop of a major Chinese city has dropped from sight amid unconfirmed reports he is seeking U.S. asylum following a quarrel with one of China's most powerful local politicians.

Wang Lijun, a crusading lawman who made his name busting crime gangs and inspired a drama on state TV, has taken leave to recover from anxiety and overwork, the city government of Chongqing said in a statement Wednesday.

Wang, who also is a vice mayor of Chongqing, was shifted out of his role as police chief last week, prompting speculation of a falling-out with the city's powerful Communist Party secretary, Bo Xilai, who is widely believed to be seeking national office.

The police chief may have fallen out of favour because his 2008-10 crackdown on criminal gangs strayed from standard procedures and clashed with the central government's current campaign to strengthen the rule of law, Beijing-based political analyst Li Fan said.

Days of speculation about his situation spiked Wednesday with online reports that he sought asylum at the American consulate in the nearby southwestern city of Chengdu on Tuesday after quarelling with Bo.

Washington confirms Wang visited consulate

In Washington, U.S. State Department spokeswoman Victoria Nuland confirmed that Wang sought and had a meeting at the consulate and later left "of his own volition." She declined to comment on whether he had sought refugee status or asylum.

She said to her knowledge, the consulate had not been in contact with Wang since the meeting.

Employees of businesses near the Chengdu consulate reported large numbers of police vehicles in the area on Tuesday night, but said the area was quiet on Wednesday.

Chinese Foreign Ministry spokesman Liu Weimin told reporters he had no information on the matter.

A city government spokesman, who like many Chinese bureaucrats would give only his surname, Ye, said he could neither deny or confirm the reports of Wang's asylum bid.

"We saw that on the Internet, too. I don't have relevant information now," Ye said.

Online search results blocked

In a sign of the sensitivity of the matter, search results for Wang and Bo were blocked on China's hugely popular Sina Weibo microblogging service and the comments sections attached to online reports about Wang were disabled.

Bo, who sits on the Communist Party's powerful 25-member Politburo, appointed Wang in 2008 to clean up the force and take on organized crime in a campaign that drew national attention, as well as criticism that it ignored proper legal procedures.

Wang, a 52-year-old martial arts expert, entered law enforcement in 1984 and served more than two decades in northeast Liaoning province, where Bo was once governor. He won a reputation for personal bravery in confronting gangs and was once the subject of a TV drama called "Iron-Blooded Police Spirits."

His law enforcement success led eventually to high political office and a seat in the national parliament, while his association with Bo gave him countrywide name recognition.

A former commerce minister, Bo is considered a leading "princeling" in the party, a reference to the offspring of communist elders whose connections and degrees from top universities have won them entry into the country's elite.

Bo garnered huge publicity for his anti-crime campaign and an accompanying drive to revive communist songs and poems from the 1950s and 1960s, spurring talk that he was seeking a promotion. Those campaigns have since fizzled, leading analysts to pull back on speculation that he might be elevated to higher office when the party begins a generational change in leadership later this year.

Chinese political analysts say Bo has been cutting ties with the advisers behind the "red songs" and anti-crime drives in hopes of reviving his political fortunes.