Three more foreign ships were struck in the Persian Gulf overnight, authorities said, as attacks intensify on vessels sailing through or near the strategically vital Strait of Hormuz.

The latest incidents come after three separate vessels sustained damage in Gulf waters on Wednesday and as Iran warns oil prices could climb to $200 a barrel.

A container ship was struck by an unknown projectile about 35 nautical miles north of Jebel Ali, a major port city near Dubai in the United Arab Emirates, the United Kingdom Maritime Trade Operations (UKMTO) center said on Thursday. The incident caused a small fire onboard, and all crew were reported to be safe.

Earlier, two foreign oil tankers were left ablaze in Iraqi waters after having been struck near the port Umm Qasr, near the city of Basra.

At least one person was killed in the attack, according to multiple media reports, citing Iraqi port officials, and 38 crew members were rescued from the ships. Iraq’s General Company for Ports was not immediately available to comment when contacted by CNBC.

Shipping traffic through the Strait of Hormuz has virtually ground to a halt since the U.S. and Israel launched airstrikes on Iran on Feb. 28. Iran has retaliated by targeting ships trying to pass through the strait, with several incidents reported in recent days.

The narrow waterway is a key maritime corridor that connects the Persian Gulf and the Gulf of Oman. Roughly 20% of global oil and gas typically passes through it.

Attacks on commercial ships in the Gulf have ratcheted up fears of a prolonged economic shock.

“Get ready for oil to be $200 a barrel, because the oil price depends on regional security, which you have destabilised,” Ebrahim Zolfaqari, spokesperson for Iran’s military command, said Wednesday, according to Reuters.

Crude prices were sharply higher on Thursday morning, as traders closely monitored supply risks and appeared to shrug off the International Energy Agency’s push to release a record 400 million barrels of oil.

International benchmark Brent crude futures with May delivery traded 5.7% higher at $97.16 per barrel, while U.S. West Texas Intermediate futures with April delivery rose 5.3% at $91.88.

The IEA on Wednesday did not set out a timeline for when the stocks would hit the market. It said that the reserves would be released over a time frame that is appropriate to the circumstances of each of its 32 member countries.