WASHINGTON— The coming week could determine whether years of negotiations over Iran’s nuclear program bear fruit - or not. Parties to the international talks are speaking out as an end-of-month deadline nears for a framework accord, while wary U.S. lawmakers plot Congress’s next move if a deal is reached.

Negotiations are making progress, but caution is warranted, according to U.S. Secretary of State John Kerry.

“We are not rushing," said Kerry. "This has been a two-and-a-half-year or more process, but we recognize that fundamental decisions have to be made now and they don't get any easier as time goes by. It is time to make hard decisions. We want the right deal.”

That view was echoed hours later by British Foreign Secretary Philip Hammond.

“We’ve made some very significant progress in some areas of those discussions, but there are other areas where we do not have agreement, and the time has come now for Iran, in particular, to take some very tough decisions if we are going to see progress made,” Hammond said.

But while most parties speak in generalities about the status of the talks, Iran is dealing in specifics. Grand Ayatollah Ali Khamenei says international sanctions must be lifted if and when an accord is reached, and pointed to dissension in the Republican-led U.S. Congress as a stumbling block. Even so, Iranian President Hassan Rouhani characterized differences as "nothing that cannot be resolved.”

Meanwhile, the chairman of the Senate Foreign Relations Committee, Bob Corker, reaffirmed his belief that Congress should weigh in on any deal that is reached.

President Barack Obama says a negotiated settlement with Iran is the best outcome, but his CIA director, John Brennan, says options will remain if no deal is struck.

Brennan warned of “tremendous costs and consequences” for Iran if it builds a nuclear weapon, adding, "There are a number of things that the United States has available to it to prevent Iran from getting a bomb.”