Senate Foreign Relations Chairman John Kerry (D-Mass.) and ranking member Dick Lugar (R-Ind.) met Tuesday afternoon with Vice President Joseph Biden to discuss the Strategic Arms Reduction Treaty, Democratic sources confirmed.

Kerry was seen rushing out the door of the Capitol to the White House shortly after the Senate lunches. The meeting was not on Biden’s schedule.

Kerry is aiming to pass the nuclear arms treaty, struck with Russian President Dmitry Medvedev in April, out of his committee before the August recess, a plan that could lead to a bitter partisan floor battle over its ratification. Minority Whip Jon Kyl (Ariz.) and other GOP colleagues have threatened to sink START over broader concerns about President Barack Obama’s nuclear weapons policy. But Kyl has been in negotiations with Biden to try to break the impasse.