[Photo Credit: Reuters]

U.S. Secretary of State Marco Rubio said the United States ​is still willing to negotiate an end to the Iran crisis but Tehran is not serious about talks, as the widening conflict disrupted two of the world’s most critical ‌energy chokepoints.

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 on Monday, opening a potential new front in the war which has killed thousands of people across the Gulf since it began on February 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 told Reuters on Monday that Tehran had received a proposal from mediators for a 10-day ceasefire in ⁠efforts to salvage the interim ceasefire agreement signed by the U.S. and Iran in June, which replaced an earlier April ceasefire.

In another sign that diplomacy remains alive, Iran’s Interior Minister Eskandar Momeni has visited ​mediator Pakistan and asked Islamabad to continue its efforts.

Rubio said Washington was “always committed to diplomacy” but doubted whether Tehran was equally committed to negotiations.

He stressed that Iran could not be allowed to control the Strait of Hormuz, arguing it would create a dangerous precedent for the world including Southeast Asian countries, many of which have territorial disputes in the South China Sea with China.

With no diplomatic breakthrough in sight, the U.S. military bombed targets across Iran for an 11th straight night on Tuesday. Tehran residents reported hearing explosions in the early hours ‌of Wednesday ⁠as Iran activated its air defences over the capital, Iran’s semi-official Fars news agency said.

Explosions were also reported in the southeastern coastal cities of Chabahar and Konarak, and two blasts were heard in Bushehr, home to Iran’s only nuclear power plant, Iran’s official IRNA news agency reported.

Earlier, Iran targeted U.S. military sites in Bahrain, Kuwait and Jordan and a tanker was hit in the Strait of Hormuz.

Iran said it had struck infrastructure belonging to Amazon (AMZN.O), opens new tab in Bahrain, where the U.S. tech company operates a regional data centre. Amazon did not comment and Reuters could not verify the report.