Nuclear weapons in Iran

Talks between Iran and six world powers hit a major snag Friday over the future size of a nuclear program that Tehran says it needs to expand to fuel atomic reactors, but which the U.S. fears could be used to make nuclear weapons.

Leading Democratic and Republican senators including New Jersey Senator Bob Menendez (D) are crafting legislation to reinstate the full force of sanctions and impose new ones if Iran doesn't make good on its pledge to roll back its nuclear program, brushing aside the Obama administration's fears about upending its diplomatic momentum.

The White House says President Barack Obama has phoned Israeli Prime Minister Benjamin Netanyahu to discuss a tentative deal with Iran over its nuclear program.

The United States and Iran secretly engaged in high-level, face-to-face talks at least three times over the past year.