The Singaporean container ship GFS Pride sank near the Strait of Hormuz on Oct. 14 after unidentified projectiles struck it. 

The Maritime and Port Authority of Singapore said the entire 21-person crew was evacuated and no injuries were reported. 

Cape Dao, a merchant ship sailing under the Antigua and Barbuda flag, also sank near the strait, weeks after a projectile had struck it on Sept. 23, killing one crew member in the strike. 

International Maritime Organization data showed the pair mark the second and third sinkings in the Middle East since the Iran war began on Feb. 28.  

Iran’s account differs; the state media said the ship struck a mine on what Iran’s Islamic Revolutionary Guard Corp called an “illegal and dangerous route,” according to The Guardian. 

However, the UK Maritime Trade Operations center pointed to unidentified projectiles for both vessels. 

One expert doubted Iran’s account of what happened. “Iran claims a naval mine; but a drone strike is more likely,” Charlie Brown, a former U.S. Navy officer and senior adviser to United Against Nuclear Iran, told CNN.

Attacks on commercial vessels have increased sharply since the start of the war

The Financial Times counted 24 vessels struck in the two weeks before Oct. 11, and the UKMTO reported six attacks on Oct. 11 alone. 

About 4.1 million barrels of oil crossed the strait on Oct. 12, which is less than 25% of the pre-war levels, according to Kpler.

Reuters spoke with two senior Iranian officials, who said Iran has adopted new methods meant to keep oil prices expensive and influence the U.S. midterms. 

U.S. fuel prices have climbed nearly 70% since the war began and Republicans fear backlash from voters. 

Tehran’s grip on the strait loosened in recent months as the U.S. military escorted tankers at night to let oil from other Gulf producers flow at close to normal levels. 

An anonymous U.S. military official told The Guardian that the Revolutionary Guards have sent unarmed lookouts out on small boats to find targets since U.S. forces destroyed a big share of Iran’s radar network. 

Singapore’s maritime authority said the attacks were “unprovoked, unjustifiable, and a breach of international law.”