RIYADH: More than 320 oil and gas tankers were among at least 2,190 commercial vessels trapped in the Arabian Gulf on Wednesday by Iran’s blockade of the Strait of Hormuz, according to new marine data, as only limited, tightly controlled traffic continued through the vital waterway.

The stranded vessels included 12 very large gas carriers and 50 very large crude carriers. Only six vessels crossed the strait between Tuesday and Wednesday, maritime intelligence firm Kpler said, far below the roughly 120 ships that transit daily in peacetime.

Vessels that have crossed were routed along a corridor approved by Iran near Larak Island off its coast, with Lloyd’s List estimating at least 48 ships have used the passage since last week, most with links to Iran or countries maintaining friendly ties with Tehran.

Iran has imposed a chokehold on the strait — through which about 20 percent of the world’s oil and gas typically pass — since it was attacked by the United States and Israel on Feb. 28. Shipowners granted passage have faced fees of up to $2 million, dubbed the “Tehran toll booth,” although Iran has indicated it may waive such charges for vessels from friendly nations, including Malaysia.