The U.S. Congress is moving forward with a massive defense bill with a controversial provision on the military detention of certain terror suspects.

Lawmakers say they made revisions to the detainee provision in an effort to avoid a threatened presidential veto.

The $662 billion bill authorizes funding for the Defense Department and the national security programs of the Energy Department. It provides money for military personnel, weapons systems, and operations in Iraq and Afghanistan for the fiscal year that began in Oct.

The bill requires military detention, subject to a presidential waiver, for foreign al-Qaida terrorists who are captured plotting to attack the United States. A change to the detainee provision exempts American citizens. But the bill does not guarantee suspected terrorists, even U.S. citizens, a trial and leaves open the possibility for indefinite detention.

The legislation prohibits the transfer or release of Guantanamo detainees to or within the United States, and prohibits the use of funds to house Guantanamo detainees in the United States.

Lawmakers in both the Senate and House of Representatives hope to approve the legislation and send it to President Barack Obama this week.

The White House had previously warned of a veto for any bill that challenges or constrains the president's authority to collect intelligence, incapacitate terrorists, and protect the nation. The Obama administration argues that the military, law enforcement officials and intelligence agents need flexibility to act on a case-by-case basis in dealing with terror suspects.