U.S. Secretary of State John Kerry says he "profoundly disagrees" with the reasoning behind decisions by two prominent Democratic lawmakers to vote against the nuclear deal he negotiated with Iran.

Speaking Friday in the Vietnamese capital, Kerry said the facts do not bear out the arguments made by the Senate's No. 3 Democrat Chuck Schumer, and the ranking member of the House Foreign Affairs Committee, Eliot Engel. He said he respects the right of lawmakers to make their own decisions about the merits of the deal, but said rejection does not offer any alternative than a drumbeat to conflict.

Schumer and Engel, both from New York, made their announcements on Thursday. Schumer is the first Democratic senator to say he will vote no on the deal.