The pirates seized the Comoros-flagged Aris 13 tanker on Monday, the first such hijacking in the region since 2012.

In their prime in 2011, Somali pirates launched 237 attacks off Somalia’s coast, data from the International Maritime Bureau showed, and held hundreds of hostages.

However attacks fell off sharply after ship owners tightened security and vessels stayed farther away from the Somali coast.

Armed pirates off the coast of Somalia who hijacked an oil tanker with eight Sri Lankan crew on board are demanding a ransom for the release of the vessel, the EU Naval Force said.

The pirates seized the Comoros-flagged Aris 13 tanker on Monday, the first such hijacking in the region since 2012.

READ: Somali pirates hijack first commercial ship since 2012

“The EU Naval Force … has received positive confirmation from the master of … Aris 13, that his ship and crew are currently being held captive by a number of suspected armed pirates in an anchorage off the north coast of Puntland, close to Alula,” the force said in a statement late on Tuesday.

Puntland is a semi-autonomous northern region of Somalia. Alula is a port town there where pirates have taken the tanker.

EU Navfor said as soon as it received an alert on the ship’s seizure, it sent patrol aircraft from its Djibouti base to try to make radio contact with the ship, and only late on Tuesday did its headquarters in London reach the vessel’s master by phone.

“The master confirmed that armed men were on board his ship and they were demanding a ransom for the ship’s release. The EU Naval Force has now passed the information regarding the incident to the ship’s owners,” EU Navfor said.

The 1,800 deadweight tonne Aris 13 is owned by Panama company Armi Shipping and managed by Aurora Ship Management in the United Arab Emirates, according to the Equasis shipping data website, managed by the French transport ministry.

In their prime in 2011, Somali pirates launched 237 attacks off Somalia’s coast, data from the International Maritime Bureau showed, and held hundreds of hostages.

That year, aid group Oceans Beyond Piracy estimated the global cost of piracy at about $7 billion. The shipping industry bore roughly 80 percent of those costs, the group’s analysis showed.