NEW YORK (AP) _ The FBI is investigating allegations that a veteran NBA referee bet on basketball games over the past two seasons, including ones in which he officiated.

According to a law enforcement official, authorities are examining whether the referee made calls to affect the point spread in games on which he or associates had wagered.

The law enforcement official, who spoke to the AP on Friday on condition of anonymity, said the referee was aware of the investigation and had made arrangements to surrender as early as next week to face charges. The official, who did not identify the referee, is familiar with the investigation but was not authorized to speak publicly about the ongoing investigation.

The law enforcement official said the bets involved thousands of dollars and were made on games during the 2005-2006 and 2006-2008 seasons.

The NBA issued a brief statement Friday: ``We have been asked by the FBI, with whom we are working closely, not to comment on this matter at this time.''

The FBI probe, which began recently, also involves allegations that the referee had connections to organized crime associates. Other arrests are expected, the official said.

The referee had a gambling problem, according to the official, and was approached by low-level mob associates through an acquaintance.

The investigation first was reported Friday by the New York Post.

Veteran oddsmaker John Avello, at the Wynn resort on the Las Vegas Strip, said that without specific information it would be difficult to identify wagering irregularities over the last two seasons.

``At this point, it's too early to know if any games were affected,'' Avello said, adding that no regulators or investigators had contacted him about the case.

Jay Kornegay, executive director of the sports book at the Las Vegas Hilton, said he had never seen any unusual activity in NBA betting, and was surprised not to have heard about an investigation until Friday.

``Whispers would have happened on the street, and we would have heard something,'' Kornegay said. ``Any type of suspicious or unusual movements, you usually hear in the industry. We're so regulated and policed, any kind of suspicion would be discussed.

``We haven't seen anything like that in the NBA that I can remember,'' he said, ``and we haven't been contacted by anybody.''

Kornegay said legal sports betting in Nevada represents a fraction of sports betting worldwide, with 98.5 perc ent of all action taken outside the state.

Gambling long has been a problem in sports, and leagues have made a point of educating players of the potential pitfalls. The NBA, for example, discusses gambling at rookie orientation, even bringing in former mobster Michael Franceze to speak.