A Pakistan-flagged tanker that entered the Persian Gulf over the weekend has become the first carrier to exit through the Strait of Hormuz with a crude cargo since a US blockade began on Monday, underscoring just how limited traffic through the vital chokepoint remains.

The Shalamar sailed just south of Iran’s Larak Island and out into the Gulf of Oman late Thursday with around 450,000 barrels of crude loaded at Das Island in the United Arab Emirates, according to ship-tracking data. The Aframax tanker, only half full, is heading to the port of Karachi to discharge its cargo on Sunday.

Transits through the narrow waterway have been mostly in single digits since US and Israeli strikes began at the end of February and, after a weekend spike, they have returned to those low levels.

A US Navy blockade now requires shipowners to clear both Iranian and American authorities to move oil and other goods from the Persian Gulf to the world.

Though a trio of supertankers laden with non-Iranian crude made it out last week, few others with such cargoes have crossed Hormuz over the past seven weeks, even before US warships closed in.

Even with apparent clearance from Iran for some Pakistan vessels, that makes the Shalamar’s crossing – after just days in the Gulf – even more unusual.