U.S. Secretary of State Marco Rubio said Wednesday that the U.S. remains open to ending the Iran crisis through talks, but accused Tehran of stalling as the conflict threatens global energy routes.

Rubio made his comments in a meeting of Southeast Asian foreign ministers a day after three oil tankers carrying Saudi crude to Asia reversed course in the Red Sea, apparently in response to threats from Yemen's Iran-aligned Houthis.

The Houthis, who control the ​coast at the mouth of the Red Sea, announced a naval blockade on Saudi Arabia Monday, opening ​a potential ⁠new front in the war which has killed thousands of people across the Gulf since it began on Feb. 28 with U.S. and Israeli attacks on Iran.

With Iran already threatening shipping through the Strait of Hormuz leading out of the Gulf, the Red Sea has served as the main alternate route out for millions of barrels of Saudi oil per day.

A senior Iranian official said Monday that Tehran had received a proposal from mediators for a 10-day cease-fire in efforts to salvage the interim cease-fire agreement signed by the U.S. and Iran in June, which replaced an earlier April cease-fire.