Senate Majority Leader Harry Reid of Nev., left, and Senate Minority Leader Mitch McConnell of Ky., right, attend a ceremony to award the Congressional Gold Medal posthumously to Constantino Brumidi in recognition of his artistic contributions to the US Capitol building, Wednesday, July 11, 2012, on Capitol Hill in Washington. (AP Photo/J. Scott Applewhite)
Senate Majority Leader Harry Reid (D-Nev.), left, and Senate Minority Leader Mitch McConnell (R-Ky.) on Capitol Hill in Washington in 2012. (J. Scott Applewhite/AP)

Senate Minority Leader Mitch McConnell (R-Ky.) on Tuesday threw cold water on the idea that Congress could pass immigration reform this year.

Speaking to reporters, McConnell called differences between the Democratic-controlled Senate and the GOP-controlled House "irresolvable."

"I think we have sort of an irresolvable conflict here," McConnell said at his weekly stakeout, according to a transcript. "The Senate insists on [a] comprehensive [bill] and the House says it won't go to conference with the Senate on comprehensive and wants to look at it step-by-step."

McConnell added: "I don't see how you get to an outcome this year with the two bodies in such a different place."

Prospects for a deal seemed to improve in recent days, with President Obama and other immigration reform advocates expressing openness to a set of "principles" laid out by the House GOP — principles that included a new path to legal status for illegal immigrants currently in the country rather than a new path to citizenship.

All sides agree that there are plenty of details left to iron out — House GOP leaders haven't even introduced a bill — but few have sounded as pessimistic  as McConnell.

McConnell, who faces challenges in both the primary and general elections in this year's election, voted against the comprehensive immigration reform measure that passed in the Senate last year and included a new path to citizenship.