(AP) -- President Barack Obama heralded a historic nuclear agreement with Iran Tuesday as an opportunity for the longtime foes to move in a "new direction," while sharply warning Congress that it would be irresponsible to block the accord.

"No deal means a greater chance of more war in the Middle East," Obama said in early morning remarks from the White House.

Obama, accompanied by Vice President Joe Biden, spoke shortly after negotiators in Vienna announced the landmark deal aimed at curbing Iran's nuclear program for more than a decade in exchange for billions of dollars in international sanctions relief. The president said the agreement, hammered out through nearly two years of negotiations, would cut off all of Iran's pathways to a bomb and give the international community unprecedented access to the country's nuclear facilities.

"This deal is not built on trust," Obama said. "It is built on verification."

Even with the world powers in agreement, Obama now must sell the virtues of the deal to skeptical lawmakers on Capitol Hill. Congress has 60 days to assess the accord and decide whether to pursue legislation imposing new sanctions on Iran or prevent Obama from suspending existing ones.

The president renewed his vow to veto any such legislation and urged lawmakers to consider the repercussions of their actions. He painted a grim scenario in which the rest of the world struck its own nuclear deals with Iran, leaving the U.S. isolated. And without the limitations and verifications included in the deal announced Tuesday, Obama said he or a future U.S. president would be more likely to face a decision about using U.S. military action to prevent Iran from building a bomb.

The White House was expected to quickly launch a campaign to win support for the deal on Capitol Hill. The president was also expected to speak Tuesday with several world leaders.