Between 2008 and 2018, Somali pirates caused havoc in the waters off the country's long coastline.
The European Union's anti-piracy force in the Indian Ocean and Red Sea, Operation Atalanta, on Thursday flagged a possible pirate attack on the Liberian-flagged merchant vessel Basilisk off the coast of Somalia.
Somali pirates caused havoc in the waters off the country's long coastline between 2008 and 2018. They had been dormant until late last year when pirate activity started to pick up again.
The EU force said in a statement that the suspected attack happened about 380 nautical miles east of the Somali capital Mogadishu while the vessel was heading north.
"One of Atalanta warships in the vicinity has been the first actor to respond. EUNAVFOR ATALANTA is taking the appropriate actions to respond," it added.
The United Kingdom Maritime Trade Operations (UKMTO) agency earlier said it had received a report of a vessel being boarded 420 nautical miles southeast of Merca, Somalia.
An unknown number of unauthorised people from two small craft were reported to have boarded the vessel, according to UKMTO.