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 said.

It's final and decisive. Any attempt [by the tanker] to move, it will be turned into scrap.

Culture Minister Al-Habib al-Amin

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 on Sunday 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.

The Libya Revolutionary Operation Room, an umbrella group of militias that answer to the interim parliament, said in a statement on its official Facebook page that the tanker was at the port and "couldn't leave because our hero revolutionaries are besieging it and preventing it from leaving," the Associated Press news agency reported.

"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 were surrounding the tanker.

Rebels controlling an oil terminal in Eastern Libya say any attempt by the central government to fire would be an "act of war".

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

The seizure of the terminals and attempted oil sales show Libya's security and economic woes which have piled up over the past two years since the toppling of former leader Muammar Gaddafi in 2011.

Source: Al Jazeera and agencies