The Olympic Council of Asia launched an investigation yesterday into possible ambush marketing or other infractions after Chinese gymnasts repeatedly made hand gestures apparently meant to mimic their sponsor's logo.

The gymnasts have a deal with Li Ning, a Chinese brand created by the former gymnast of the same name, who is best known internationally for lighting the cauldron during the 2008 Beijing Olympics opening ceremony.

Several gymnasts put a hand on their chest with thumb up and fingers pointed like a gun during competition and medals ceremonies this week.

"This is a gesture that's required as part of the deal with our sponsor," men's individual all-around gold medalist Teng Haibin said after his win on Monday, explaining that it was meant to resemble Li Ning's "L" shaped logo. Chinese athletes of various sports have been photographed making the gesture for several years.

Li Ning is not an official Asian Games sponsor and such behavior could be considered ambush marketing, which is forbidden at international sporting events such as the Asian Games.

Authorities are investigating "what exactly does it mean officially. I don't want to go by hearsay," said Vinod Tiwari, director of international relations for the Olympic Council of Asia. He expected to have an answer by today.

Teng and Chinese silver medalist Lu Bo flashed the sign during their medal ceremony, and Japanese bronze medalist Hisashi Mizutori gamely followed suit although he later said he had no idea what it meant.

The gesture had raised questions because it looked like the Chinese athletes were pretending to point guns at Mizutori, at a time when tensions between their countries have been running high over a territorial dispute.

Women's gymnasts He Kexin and Huang Qiushuang also made the sign in front of TV cameras during individual competitions on Tuesday.

Li Ning competitor 361 Degrees is a major Asian Games sponsor, but a company executive reached yesterday declined to comment on the gymnasts' behavior.

"I noticed some athletes making that gesture but I thought it didn't have any meaning," said Chen Yuanfeng, vice president of investor relations.