FOXBOROUGH, Mass. (AP) — Patriots coach Bill Belichick says he doesn't know how footballs became deflated during the game that got his team to the Super Bowl.

But Belichick declined to answer questions Thursday after saying he knew nothing about accusations that his team cheated with underinflated footballs in its win against the Colts in the AFC championship game.

The NFL is investigating.

Belichick says quarterbacks, kickers and other specialists have their own preferences on footballs. But he says he gives them no sympathy when they talk about those preferences, and forces players to practice under bad ball conditions.

Belichick says the Patriots going forward will inflate footballs to a safe level to prevent them from going under allowable air pressure during games.

Patriots quarterback Tom Brady is expected to address reporters later Thursday.