The human rights group Amnesty International blasted President Barack Obama for signing the National Defense Authorization Act (NDAA) into law on New Year’s Eve.

The $662 billion defense spending bill contained highly controversial provisions regarding the military detention of terrorism suspects. While signing the bill, Obama issued a signing statement -- a controversial way for the president to circumvent Congress' intent -- in which he pledged that the new laws would not violate Americans' constitutional rights.

But Amnesty said the signing statement was not enough.

"Despite expressing serious reservations, the Obama administration has paved the way for legislation that will authorize indefinite detention. The bill places enormous power in the hands of future Presidents, and the only answer the President has is to say 'trust me,'" the group said in a statement.

"Once any government has the authority to hold people indefinitely, the risk is that it can be almost impossible to rein such power in. President Obama has failed to take the one action – a veto – that would have blocked the dangerous provisions in the NDAA. In so doing, he has allowed human rights to be further undermined and given al Qaeda a propaganda victory."

Amnesty has been a long-time critic of the counterterrorism detentions at Guantanamo Bay in Cuba, which the group claims are unlawful and a violation of human rights. By signing the NDAA into law, Obama also prevented the closure of the prison facility at Guantanamo.