New York, NY (SportsNetwork.com) - The NFL issued a statement Friday regarding its investigation into allegations the New England Patriots used underinflated balls during the AFC Championship Game and said the early evidence supports the initial conclusion but that the process is ongoing.

The Patriots rolled to a 45-7 win over the Indianapolis Colts last Sunday in a rain-soaked game at Gillette Stadium and reports began to surface in the hours after the contest that balls were not correctly inflated, which would apparently allow for a better grip in inclement weather.

Citing league sources, ESPN.com reported Tuesday night that 11 of the 12 balls used by the Patriots during the game were underinflated by two pounds of air pressure per square inch (PSI).

NFL rules mandate game balls, which are inspected by the referee, be inflated to 12 1/2 to 13 1/2 PSI.

"The playing rules are intended to protect the fairness and integrity of our games," the league said in its statement Friday. "We take seriously claims that those rules have been violated and will fully investigate this matter without compromise or delay.

"The investigation is ongoing, will be thorough and objective, and is being pursued expeditiously. In the coming days, we expect to conduct numerous additional interviews, examine video and other forensic evidence, as well as relevant physical evidence.

"While the evidence thus far supports the conclusion that footballs that were underinflated were used by the Patriots in the first half, the footballs were properly inflated for the second half and confirmed at the conclusion of the game to have remained properly inflated.

"The goals of the investigation will be to determine the explanation for why footballs used in the game were not in compliance with the playing rules and specifically whether any noncompliance was the result of deliberate action. We have not made any judgments on these points and will not do so until we have concluded our investigation and considered all of the relevant evidence."

The league said Friday the investigation is being led jointly by NFL executive vice president Jeff Pash and Ted Wells of the law firm of Paul Weiss. Wells was the league's investigator into last season's bullying scandal involving the Miami Dolphins.

According to the statement Friday, the league began its investigation Sunday night and has already conducted nearly 40 interviews. Game officials and Patriots personnel were among those included in those early discussions, although New England quarterback Tom Brady said Thursday he had not yet been contacted.

On Thursday, both Brady and Patriots coach Bill Belichick addressed the situation and each denied any wrongdoing.

Belichick was first to speak on Thursday morning and said he was "completely and totally unaware" of the issue, adding he was "shocked" to hear the reports on Monday morning.

Brady on Thursday afternoon said he "didn't alter the balls in any way" and "would never break the rules."

The Patriots, who will play Seattle in the Super Bowl, have pledged their full support of the investigation and have made personnel, as well as other information, available to the league.

If the NFL finds the Patriots deflated footballs intentionally, they could be subject to penalties similar to ones levied after the team was found to have videotaped defensive signals used by the New York Jets during a game in September 2007.

Those penalties included a $500,000 fine for Belichick, a $250,000 fine for the team and the loss of a draft pick.