The US Navy has alerted mariners to the fact that pirates based in the Gulf of Aden are expanding their raids into the Red Sea.

The navy’s fifth fleet headquartered in Bahrain has notified merchant vessels that the pirates have changed tactics to include more night raids to avoid the stepped-up presence of international navies.

The navy has also warned vessels to be on guard in the Red Sea following a confirmed attack in the southern end of the Red Sea in May.

Pirates have also reportedly extended their operations to include the Seychelles Islands to avoid foreign navy ships in the Gulf of Aden shipping lane that connects Asia with Europe.