US Central Command has said it intercepted a merchant vessel trying to get through the blockade of Iran, Reuters reports.

Here are some details: The ship, identified as the Sevan, was part of a 19-vessel “shadow fleet” transporting Iranian oil and gas products to foreign markets, the US military said.

Central Command said it was intercepted in the Arabian Sea by a US Navy helicopter from the guided-missile destroyer USS Pinckney and was “currently complying with US military direction to turn back to Iran under escort.”

The shadow fleet vessels have been sanctioned by the US Treasury Department for activities related to transporting billions of dollars’ worth of Iranian energy, oil and gas products, including propane and butane, to foreign markets, Central Command said.

Since the blockade began, 37 ships have been “redirected,” the US military said.