Obama meets Saudi king with Iran on agenda

By Roberta Rampton RIYADH (Reuters) - U.S. President Barack Obama arrived in Riyadh on Wednesday to meet Saudi Arabia's King Salman ahead of a summit with other Gulf Arab leaders on Thursday and with regional tensions with Iran likely to be high on the agenda. Obama comes to the world's top oil exporter for a fourth and likely last time as president hoping to reassure it and other Gulf allies of Washington's commitment to their security, and to seek ways to reduce sectarian tensions in the regio