US President Barack Obama was in Riyadh Friday to discuss with Saudi officials ways to "best empower" Syria's moderate opposition, including militarily, a senior White House official said.
Cooperation over support for the opposition in the past few months helped improve strained links between Washington and its traditional ally, deputy national security advisor Ben Rhodes told reporters travelling with Obama on board Air Force One.
"That will definitely be one of the main topics of conversation is how do we best empower the moderate opposition inside of Syria politically, militarily as a counterweight to (President Bashar) Assad," he said.
Saudi Arabia has strong reservations about efforts by Washington and other major world powers to negotiate a deal with Iran on its nuclear programme.
It is also disappointed over Obama's 11th-hour decision in September not to take military action against the Syrian regime over chemical weapons attacks.
Saudi Arabia is a major backer of the Syrian rebellion, and has been pushing for a stronger international stance against Assad.
"We have been working in close cooperation with the Saudis and other countries in the region to coordinate our assistance for the Syrian opposition over the course of the last several months," said Rhodes.
"Our relationship with the Saudis is in a stronger place today than it was in the fall (autumn) when we had some tactical differences about our Syria policy," he added.
The Syrian opposition has long been calling for world powers to supply it with sophisticated weapons, especially shoulder-launched anti-aircraft rockets, so it can more effectively battle Assad's forces.
Saudi Arabia has echoed such calls, insisting at an Arab summit this week of the need for a change in the military balance on the ground, where Assad forces, aided by Lebanon's Shiite Hezbollah fighters, have been making significant advances against rebels.
But Washington has stressed that it has concerns over supplying rebel fighters with man-portable air-defence (MANPAD) weapons, fearing these might end up in the hands of extremists.
"We have made clear that there are certain types of weapons, including MANPADs, that could pose a proliferation risk if introduced into Syria," said Rhodes.
"We continue to have those concerns," he added, insisting on not getting into specifics about weapons.