The Culture Ministry said Gaga's use of the flag, tied to the back of a motorcycle while dressed in provocative outfit, was "inappropriate" and disrespectful to its people, a ministry official told Reuters, requesting anonymity because she was not authorized to speak to the media.

Lady Gaga performed before 50,000 fans in Bangkok on May 25 as part of a world tour that caused controversy in the Philippines and South Korea and prompted organizers to cancel her show in Indonesia after Islamic groups objected to her "vulgar" style.

The Grammy Award winner had already upset some Thais when she Tweeted to her 24 million followers upon arrival in Bangkok her plans to buy a fake Rolex watch at one of the city's ubiquitous street markets.

The Tweet stirred debate in Internet chat rooms and on web boards, resulting in the Commerce Ministry lodging a complaint with the United States embassy, saying Gaga was undermining its efforts to stamp out piracy.

Many of Bangkok's indoor and outdoor markets are renowned for selling cheap replicas of coveted designer handbags and accessories. Gaga has made no comment on her Tweet.

The Culture Ministry said police would not prosecute Lady Gaga but it filed the formal complaint to show dissatisfaction.

The ministry has long been criticized for being overzealous in its censorship of films, music, television and some Western cultural practices in an attempt to preserve the traditional conservative values of a country that also has a reputation for racy night life and neon-lit go-go dancing bars.

(Reporting Amy Sawitta Lefevre; Editing by Martin Petty and Ron Popeski)

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