Iran has reimposed strict control over the Strait of Hormuz less than a day after declaring the vital shipping lane open following a cease-fire between Israel and Lebanon. The move has renewed uncertainty in one of the world’s most important maritime corridors, with Iran saying it would maintain tight oversight unless the United States ended its blockade of Iranian ports.

Two vessels were reportedly struck in separate incidents, according to the United Kingdom Maritime Trade Operations organization. One tanker was fired upon by gunships linked to Iran’s Islamic Revolutionary Guards Corps, while a container ship was hit by a projectile that damaged several containers. Crews were reported safe, but multiple ships reversed course after the attacks.

India summoned Iran’s ambassador to express deep concern over the incidents, as both affected ships were sailing under the Indian flag. Shipping data showed several other vessels turning away near an Iranian island that has become a checkpoint, and major shipping companies, including Maersk, said they would avoid the strait until safety could be assured.

Recent weeks have seen at least 20 vessels attacked, according to the International Maritime Agency. Analysts say the coming days will be critical in determining whether commercial traffic resumes at normal levels or remains severely constrained amid heightened security risks.