CAIRO — The Islamist party that leads the new Egyptian Parliament is threatening to review the 1979 peace treaty with Israel if the United States cuts off aid to the country over a crackdown on American-backed nonprofit groups here.

The Obama administration and Congressional leaders have already warned Egypt that the United States might cut off its annual aid to the country, which in the most recent budget came to $1.3 billion in military supplies and about $250 million in other subsidies, including some money directed to the nonprofit groups under investigation. At least two senators have introduced legislation that could curtail the aid, and the Brotherhood released its statements on Thursday as the House Foreign Affairs Committee held a hearing on the matter.