SHABWA PROVINCE — Yemen's Coast Guard is attempting to recover an oil tanker that was hijacked off Yemen's southeastern Shabwa province and is now heading towards Somalia, according to a coastguard statement. Armed assailants boarded and took control of the M/T Eureka before steering it through the Gulf of Aden toward the Somali coast.

The coastguard said it was working with international partners and relevant authorities in the Gulf of Aden to recover the vessel and ensure the safety of those on board. The fate of the crew remains unknown. The coastguard added that its capabilities are limited due to Yemen's dire economic situation.

The hijacking of the M/T Eureka is the fourth attack near Somalia in recent weeks, as pirate activity in the Gulf of Aden near Somalia has increased. The United Kingdom Maritime Trade Operations has raised the piracy threat level along the Somali coast to "substantial" and warned vessels to "transit with caution." The European Union's naval forces patrolling the region said the conflict has given piracy groups a "window of opportunity."

Ship hijackings off the Somali coast have become more frequent since the U.S. and Israel began military operations against Iran in February, according to available accounts.

Somalia's coastline was the world's worst region for piracy from the early to mid-2000s. More than 200 piracy attacks were recorded in 2011 alone, according to EU naval force data. The World Bank estimated that at its peak, piracy was costing the global economy as much as $18 billion a year. An international naval coalition eventually suppressed the piracy threat, reducing attacks to nearly zero by 2014.