Libyan government forces and loyal militia fighters have besieged a North Korea-flagged tanker that a rival militia hoped to use to export oil in defiance of central authorities, officials say.

Al-Habib al-Amin, the country’s culture minister and a top aide to Libya’s prime minister, told reporters in a televised news conference that government forces including navy vessels were deployed to al-Sidra port to stop the tanker.

“It’s final and decisive. Any attempt (by the tanker) to move, it will be turned into scrap,” al-Amin said.

In case it doesn’t surrender, the tanker will be shelled completely.

The Libya Revolutionary Operation Room, an umbrella group of militias groups that answer to the interim parliament, said in a statement on its official Facebook page that the tanker is at the port and “couldn’t leave because our hero revolutionaries are besieging it and preventing it from leaving.

“In case it doesn’t surrender, the tanker will be shelled completely,” the statement said. In a second note, the operation room said that 22 fishing vessels mounted with mortar and rocket launchers are surrounding the tanker.

Al-Sidra is one of the biggest ports in the country and has been under militia control since the northern summer, slowing the country’s oil output – once estimated at 1.6 million barrels a day – to a trickle.

For months, the Libyan government has been coaxing and threatening to use force against the eastern militias demanding greater self-rule and equal distribution of oil wealth among Libya’s three historic regions. The militias also ask for an investigation into allegations of corruption marring oil sales.

The country’s prosecutor general has issued an arrest warrant for the tanker captain and its crew members while ordering the tanker be confiscated.

US State Department spokesperson Jen Psaki said in a statement on Sunday night, “The United States is deeply concerned by reports that a vessel sailing under the name Morning Glory is loading a cargo of illicitly obtained oil at the Libyan port of Al-Sidra.

This action is counter to law and amounts to theft from the Libyan people. The oil belongs to the Libyan National Oil Company and its joint venture partners,” including US companies.

“Any oil sales without authorisation from these parties places purchasers at risk of exposure to civil liability, penalties and other possible sanctions in multiple jurisdictions.”