US Secretary of State John Kerry said in Riyadh Monday that Washington will work to "empower" Syria's opposition, while warning arch-foe Iran that time for talk on Tehran's nuclear ambitions could run out. Kerry, on his first tour to the region since taking office, also met over lunch with Palestinian president Mahmud Abbas, who flew in to Riyadh unannounced late on Sunday. Kerry stressed that there was no question of arming the Syrian opposition, even as his Saudi counterpart Prince Saud al-Faisal insisted on the right of Syrians to self-defense, AFP reported