Major shipowners have begun moving vessels through the Strait of Hormuz since the U.S. and Iran signed an agreement Wednesday, according to maritime data company Lloyd’s List Intelligence.

In a media briefing, Richard Meade, editor in chief of Lloyd’s List, said for the first time in 110 days, ships owned by major companies are transiting the strait after effectively being marooned there since February.

The strait is a critical passageway for the world’s oil and natural gas. Its closure has created a historic energy crisis.

They did not give data on how many ships have passed through the strait as of Thursday. Tankers controlled by major ship owners Grimaldi Group, Cosco, Knutsen and NYK have passed through the strait. And two Iran-flagged, National Iranian Tanker Company-owned, sanctioned crude oil tankers have entered the strait, according to Lloyd’s List.

Phillip Belcher, marine director of Intertanko, a trade group for global independent tanker owners, said the main central route of the Strait of Hormuz is still closed and has an estimated 80 mines that need to be cleared. But ships have been passing through the smaller northern route, which goes through Iranian waters, and the southern route, which goes through Omani waters.

“Those two routes now seem to be fully open,” Belcher said.

LLoyd’s list estimates 550 merchant ships will need to prepare to exit the gulf, including 160 tankers, 200 bulk carriers, 60 container ships and 10 vehicle carriers.