NEW YORK -- 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 investigation first was reported Friday by the New York Post.

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 2006-2007 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 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.

"These accusations, if true, are extremely serious and we have been in discussions with the NBA regarding this matter," Lamell McMorris, head of the NBA Referees Association, told Bloomberg News. "In light of the fact that this is an ongoing federal criminal investigation, we have nothing further to say at this time."

The Associated Press contributed to this report.