At a tense time in U.S.-Saudi relations over how to handle Iran and Syria, President Obama met with King Abdullah of Saudi Arabia in his desert camp outside of Riyadh Friday, seeking to reassure him that the relationship is on solid ground despite some 'tactical differences' in recent months. It was Obama's third meeting with King Abdullah in the last six years..

The White House's deputy national security adviser, Ben Rhodes, told reporters aboard Air Force One on the flight to Saudi Arabia  that the trip was  "an opportunity to reaffirm the importance of the relationship, to talk about Gulf security, Syria, Iran, Middle East peace, and other regional developments -- in Egypt, for instance."

The Saudi king’s main concerns were said to be the threat of Iran's nuclear program and Iran's backing  of the Bashar Assad regime in Syria.

On Syria, Rhodes said a main topic of the meeting was how to best empower the opposition militarily and politically, but "there's not a specific announcement forthcoming around additional assistance," according to pool reports. In recent months, the United States and Saudis have tried to improve coordination on that front, he said. "We believe we've made good progress" in improving coordination about "who we're providing assistance to and what types of assistance we're providing."

Rhodes said that coordination has helped put the U.S. relationship with Saudi Arabia “in a stronger place today than it was in the fall when we had some tactical differences about our Syria policy.” Saudi officials had hoped for a U.S. military strike against Syria, and were angry that Obama instead backed a plan to strip Syrian President Bashar Assad of his chemical weapons.

On Iran, Rhodes said Obama and Secretary of State John Kerry will make it clear that, even as the United States pursues a nuclear deal, concerns about Iran's behavior in the region "remain constant." "We're going to keep the pressure on all those other issues."

Also on Friday, in separate developments, Kerry sought to keep peace talks between Israel and the Palestinians from falling apart over Israel’s refusal to free about two dozen Palestinian prisoners, who were scheduled to be released Saturday.

“The Israeli government has informed us through the American mediator that it will not abide with its commitment to release the fourth batch of Palestinian prisoners scheduled for tomorrow,” Palestinian spokesman Jibril Rajub told the AFP news agency.