Senate Republicans on Wednesday night defied President George W. Bush by requiring the Pentagon to follow army regulations for the interrogation of prisoners, a move the White House argues would limit US ability to prosecute the war on terrorism.

The Senate voted 90 to 9 to approve a bipartisan amendment to the defence appropriations bill, sponsored by John McCain, a senior Republican member of the Senate armed services committee, that will require the Pentagon to follow the US army field manual on intelligence interrogation.