Amid escalating Iran-U.S. tensions that has flared over the downing of a drone, U.S. Secretary of State Mike Pompeo held talks Monday with the Saudi king and crown prince as part of a diplomatic push to build a global coalition against Iran.

Pompeo wrote on Twitter that he had a "productive meeting" with King Salman and discussed "heightened tensions in the region and the need to promote maritime security" in the Strait of Hormuz near the Persian Gulf, through which roughly a fifth of the world's traded oil passes.

The regional stops, including the United Arab Emirates (UAE), made on his way to India, may be aimed at reassuring Washington's Sunni Gulf Arab allies that the White House remains committed to maintaining pressure on Shiite Iran following Trump's last-minute about-face, which likely raised questions about U.S. willingness to use force against the Islamic Republic.

The "global coalition" against Iran that the U.S. hopes to set up will fail, Tehran said yesterday. "It's nothing new ... But this, too, like the previous fragile coalitions, won't reach its goals and will eventually fail," Iranian Foreign Ministry spokesman Abbas Mousavi said, according to the ministry's website.

Iran is an influential country, both regionally and further afield, Mousavi said, which makes forming a coalition "no easy task." Pompeo's visit came at a time of growing antagonism between Iran and the U.S. following two waves of still unexplained attacks on Gulf shipping, which Washington has blamed on Tehran. The Strait of Hormuz is a vital corridor connecting the energy-rich states of the Middle East with markets in Asia, Europe, North America and elsewhere. According to the Energy Information Administration (EIA), 35 percent of the world's seaborne oil passes through the Strait of Hormuz. Iran, which is struggling with crippling U.S. sanctions, has repeatedly warned in the past that it could block the strait in a relatively low-tech, high-impact countermeasure to any attack by the U.S. Doing so would disrupt oil tankers traveling out of the Gulf region to the Indian Ocean and global export routes.

President Donald Trump yesterday told other countries to protect their own Gulf oil shipments, declaring that the U.S. has only limited strategic interest in the "dangerous" region.

In a pair of tweets, Trump said U.S. aims regarding Iran boil down to "No Nuclear Weapons and No Further Sponsoring of Terror." As for Iran's threats to shut sea lanes used to transport a large portion of the world's oil exports through the Persian Gulf, Washington is not concerned, Trump said.