PARIS, April 17 -- Three Iranian oil tankers carrying a total of five million barrels of crude have become the first such loaded vessels to leave the Gulf through the Strait of Hormuz since a US blockade came into force, the tracking firm Kpler told AFP on Friday.

The Deep Sea, Sonia I and Diona, all under US sanctions, passed the strategic strait on Wednesday after leaving Iran's Kharg Island, having loaded on April 2, 8 and 9 respectively, according to the maritime data company.

Washington has imposed a blockade on Iranian ports since Monday, intended to prevent Tehran from exporting its oil.

No Iranian tanker had left the Gulf through the Strait of Hormuz with a cargo of crude oil since the Starla on April 10.

Maritime data trackin...