The United States launched fresh strikes on Iran Friday after Tehran-backed Houthi rebels attacked oil tankers in the Red Sea, marking an escalation that pushed crude prices past $100 a barrel. But the Houthis opened a new front in the war this week when they attacked vessels in the Red Sea, intensifying fears over world crude supplies. Advertisement AdvertisementAdvertisement AdvertisementYemen's Houthis joined the conflict this week, declaring a blockade of Saudi ports and claiming attacks on tankers. - Houthis step in -While Trump has returned to war and his fierce rhetoric, the conflict is proving increasingly unpopular at home. The new threat in the Red Sea endangers top oil producer Riyadh's ability to bypass the strait for some crude exports.