Only five ships crossed the Strait of Hormuz on Monday as traffic in the crucial waterway slowed to a near halt, according to data from Kpler, a firm that tracks maritime traffic.

On Saturday, 24 ships crossed the strait after Iran had declared the passage open to commercial vessels at the start of a cease-fire between Israel and Lebanon. But within 24 hours, Iran reversed course and said it had returned the strait “to its previous state.”

Only one made it through on Sunday, according to Kpler figures, which refer to ships carrying crude oil and chemicals, but not cruise ships or container ships. Kpler uses satellites and transponders to track the movement of ships.

The United Kingdom Maritime Trade Operations center, which is administered by Britain’s Royal Navy, said that two vessels had been hit, according to a notice published on Saturday. In one instance, gun ships operated by Iran’s Islamic Revolutionary Guards Corps fired at a tanker without radio warning, the British organization said. In the second incident, a container ship was hit by “an unknown projectile” that damaged some of the containers. Those ships, and several others, then reversed course. The attacks over the weekend were the first attacks since the cease-fire began on April 8.

At least 20 vessels have been attacked in recent weeks, according to the International Maritime Organization, a United Nations agency.

And most shipping companies said the situation was too precarious to try to navigate ships through the strait. The average number of vessels crossing the Strait of Hormuz before the war was more than 120 per day.

On Monday, the five ships that crossed the strait were the Nova Crest, the Starway and the Axon 1, the Atlantic Harmony and Meda, according to Kpler.

A two-week cease-fire between the United States and Iran, which is scheduled to expire on Wednesday in the Gulf, remained precarious on Monday. A U.S. Navy destroyer fired on an Iran-flagged vessel that was trying to evade a blockade on Sunday. President Trump said a U.S. delegation would head to Pakistan for more peace talks, but the spokesman for Iran’s foreign ministry said there were “no plans” in place for the next round of peace talks there.