Vortexa, an analytics firm focusing on global energy and freight markets, says it recorded 34 movements of sanctioned and Iranian-linked tankers in and out of the Persian Gulf in the week after the US imposed a naval blockade of Iranian ports, The Associated Press reports.

The firm said it identified 19 outbound and 15 inbound movements of such vessels between April 13 and April 20.

Six of those outbound movements were “confirmed laden with Iranian crude, representing about 10.7 million barrels”, it said in an email to The Associated Press.

It was not immediately clear whether all those barrels reached markets overseas, the report noted.