When T-shirts were spotted in the VIP section of a World Cup match, officials knew something was up.

And that led to the arrest of a World Cup volunteer for allegedly selling about 50 premium tickets, officials said Saturday.The volunteer for the tournament's French organizing committee CFO was arrested in the northern border city of Lens where the match took place, the officials said on condition of anonymity.

The man, who was not identified, was among 1,000 volunteers who worked at the stadium.

French radio reported that officials were tipped off when the fans who bought the tickets showed up in T-shirts in the usually well-dressed "presidential section."

It was the latest problem involving tickets for World Cup organizers. Most have involved travel agencies that allegedly oversold tickets or failed to deliver them.

On Friday, the head of a U.S. ticket agency for the World Cup was placed under formal investigation - one step short of being charged - for alleged fraud. He reported the theft of thousands of tickets officials said were already sold, judicial sources said.

Douglas Knittle, president and general manager of Prime Sports International, was placed under judicial controls, preventing him from leaving the country, the sources said on customary anonymity.

Critics have also said distribution plans were unfairly weighted toward French fans and sponsors. Of the 2.6 million tickets printed, more than 962,000 were earmarked for supporters in France, while commercial partners snapped up 436,000.

In London, the English Football Association complained that the official ticket allocation for Tuesday's match against Argentina will create a flood of demand on the black market and fresh fears of violence.

The allocation of 2,049 for the second-round game is smaller than for any of England's group games and could provoke problems as frustrated fans compete for black market tickets.

FA deputy chief executive Pat Smith said the association was trying to negotiate more tickets for the Saint-Etienne match.