WASHINGTON - US President Barack Obama on Wednesday called King Abdullah bin Abdulaziz Al Saud of Saudi Arabia to discuss the negotiations over Iran's nuclear program, as the kingdom had shown unhappiness over Washington's policies toward Egypt, Syria and Iran.

In the phone talks, Obama shared the details of the first-step agreement reached on Sunday in Geneva between Iran and the P5+1 group of Britain, China, France, Russia, the United States plus Germany, the White House said.

The president reaffirmed the importance of Iran "following through on its commitments" of curbing some of its nuclear activities in exchange for eased sanctions by the major powers, the White House said in a readout of the talks.

The two leaders agreed to consult regularly as the six powers pursue follow-up negotiations with Iran with a view to striking a comprehensive deal within the next six months.

"President Obama reiterated the firm commitment of the United States to our friends and allies in the Gulf," the White House said.

Riyadh declined a nonpermanent seat on the UN Security Council in October in protest against Washington's approaches to Egypt, Syria and Iran. US Secretary of State John Kerry visited the kingdom early this month and met with the king.