A Thai army general has been arrested on suspicion of extortion in a notorious Bangkok red light district, officials said Thursday, in a rare case of authorities prosecuting a member of the military.

Major-General Jenronnarong Detwan, 56, was arrested by the military early Wednesday at a hotel near the seedy Patpong area charged with extorting money from street vendors, the Defence Ministry told AFP.

"He is the most senior member of the military ever arrested for extortion," said the ministry's Lieutenant Colonel Burin Tongprapai, who led the arrest.

Patpong is a strip of go-go bars catering mainly to foreigners attracted by Thailand's huge sex industry.

The military, who took power in a May 22 coup, began investigating the general after complaints from street vendors who hawk everything from cut-price DVDs to counterfeit handbags and watches.

Jenronnarong has denied the charge.

"But he said he took money from traders to pay the owners of the copyrighted goods," according to Burin, who added the general is now under both criminal and military investigation.

Junta spokesman Colonel Winthai Suvaree confirmed the arrest.

The military also arrested four civilians accused of working with Jenronnarong.

Since seizing power, Thailand's new junta rulers have vowed to root-out corruption across the kingdom.

The coup followed nearly seven months of protests against the toppled government which were pock-marked by deadly violence.

The junta has since suspended democracy, muzzled dissent and imposed sweeping curbs on freedom of expression as it bids to re-write the constitution and enact political reforms before holding new elections around October next year.