President Barack Obama declared an interim nuclear deal with Iran an ‘‘important first step’’ that cuts off the Islamic republic’s most likely path toward a bomb.

‘‘These are substantial limitations which will help prevent Iran from building a nuclear weapon,’’ Obama said at the White House late Saturday.

The president spoke shortly after the U.S. and five international partners agreed to a short-term deal with Iran that is aimed at paving the way for a broader agreement to curb Tehran’s disputed nuclear program. Under terms of the deal, Iran agreed to halt progress on key elements of its nuclear program in exchange for modest relief from U.S. economic sanctions.

Obama pledged to hold off from imposing new sanctions during the terms of the six-month agreement, a position likely to anger some in Congress who have been pushing for even tougher penalties against Iran.

‘‘If Iran does not fully meet its commitments during this six-month phase, we will turn off the relief and ratchet up the pressure,’’ he said.  (Associated Press)