John McCain, the presumptive Republican nominee: "He is a politician. Active discussions are taking place, and it's between two sovereign countries, and I'm confident that, over time, we will reach an agreement that is in the best interests of the United States and of Iraq."

Barack Obama, the presumed Democratic nominee, did not address the issue and his campaign did not comment.

Zalmay Khalilzad, the U.S. ambassador to the United Nations: "In negotiations about difficult issues there are phases when people get frustrated. I wouldn't read too much into any particular statement at any one time. The two countries are committed to reaching an agreement."

Iraqi Deputy Prime Minister Barham Salih: "Our American allies need to understand and realize that this agreement must be respectful of Iraqi sovereignty. We need them here for a while longer, and they know they have to remain here for a while."

Armand Cucciniello, U.S. Embassy spokesman in Baghdad said: "We are looking forward to a successful conclusion of the negotiations."