U.S. Secretary of State John Kerry said on Wednesday he had discussed ways to revive a "frayed" Syrian truce and get aid into besieged communities with Iranian Foreign Minister Mohammad Javad Zarif, who had indicated "how this can be achieved".
Addressing a seminar in Norway on conflict resolution, Kerry said he was working to put in place a "genuine" ceasefire agreement among warring factions, despite repeated violations of the Feb. 27 truce.
The 70-minute meeting with Zarif took place soon after Kerry's arrival in Norway from the Dominican Republic. The two also discussed the implementation of the 2015 Iran nuclear deal and related sanctions relief for Tehran, the U.S. State Department said.
Iran has complained that concerns among banks about breaking remaining sanctions had deterred investment since the deal was signed in July. Washington has said Iran needs to do more to make itself attractive to Western companies.
On Syria, where the war is in its sixth year, Kerry said he still hoped to be able to fully stop the fighting. The February agreement has largely collapsed and there has been little progress in negotiating a political transition that is supposed to begin on Aug. 1.
Backed militarily by Iran and Russia, Syrian President Bashar al-Assad has shown no willingness to compromise, much less step aside to allow a transition Western powers maintain is the solution to the conflict.
At Wednesday's meeting Zarif had "indicated to me possibilities of how this can be achieved", Kerry said.
"It is very clear that the cessation of hostilities is frayed and at risk," Kerry told delegates at the forum near Oslo.
"Russia needs to understand that our patience is not infinite, and in fact very limited, with respect to whether or not Assad is going to be held accountable," he said.
"My hope is we will open some political space to try and resolve one of the most complex international challenges the community has faced in at least a generation," he said.
Damascus said on Wednesday that German special forces were present, alongside French and American military personnel, in northern Syria, an accusation denied by Germany.