U.S. Secretary of State John Kerry is in Saudi Arabia in a bid to reduce tensions between that country and Middle East rival Iran.
Kerry is expected to participate in a meeting of foreign ministers of the six-nation Gulf Cooperation Council. He will also hold talks with representatives of the Syrian opposition ahead of UN-sponsored talks with the government of Syrian President Bashar al-Assad.
In a joint press conference with Saudi Foreign Minister Adel al-Jubeir, Kerry stressed the "United States remains concerned about some of the activities that Iran is engaged in in other countries."
Jubeir said, "I think the United States is very aware of the danger of Iran's mischief."
Sunni Saudi Arabia cut ties with predominantly Shi'ite Iran earlier this month after demonstrators attacked the Saudi Embassy in Tehran and a consulate in Mashhad.
Those actions were prompted by Riyadh's execution on January 2 of Shi'ite cleric Nimr al-Nimr, one of 47 people executed after being convicted of terrorism.
Meanwhile, U.S. Vice President Joe Biden is in Turkey, where he will also discuss the crisis in Syria.