The raid took place on the 1,740-teu Hansa Marburg (built 2007) late on Monday night, 130 miles south-west of Malabo in Equatorial Guinea.
Pirates boarded the vessel and seized two Ukrainians, a Russian and a man from Kiribati.
None of the other 14 men left on board were harmed and L&B is in the process of contacting the families of those involved.
The