WASHINGTON — Commercial ships transiting the Strait of Hormuz are under the heaviest spate of attacks since the US launched its war against Iran in February.

At least six ships were hit by projectiles while attempting to transit the waterway between Oman and Iran on Sunday, marking the highest number of successful maritime attacks reported on any single day since the start of the war.

The strikes occurred on both sides of the strait as well as within it, reported the United Kingdom Maritime Trade Operations Centre, which monitors maritime security in the region. Two crude oil tankers, a cargo vessel and three refined products tankers were hit, the UKMTO reported. At least two Indian crew members were reported missing in one of the incidents, India’s Foreign Ministry said.

Iran’s Islamic Revolutionary Guard Corps claimed one of the tankers, a VLCC supertanker, belonged to ADNOC, the United Arab Emirates’ state petroleum firm. ADNOC has not publicly confirmed the attack.