At least one pirate was reported killed in the exchange, but Commander Harbour said he could not confirm any deaths.
The fatality was believed to be the first caused by private security personnel hired to counter the threat of piracy off Somalia, Commander Harbour said.
Commander Harbour said a helicopter from the Russian destroyer, the Marshal Shaposhnikov, approached the tanker "and was fired upon by pirates".
In one pirate skiff, which was riddled with bullets, the boarding party found three pirates and the body of a fourth who had been hit by small arms fire, Commander Harbour said.
The Russian sailors offered a "robust" response, Commander Harbour said, and the pirates, thought to be from Somalia, eventually surrendered to a boarding party that took control of the tanker.
Commander Harbour said a helicopter launched from the deck of a Spanish naval vessel had spotted a yacht towing a skiff, possibly one used by pirates, about 200 miles off the Somali coast at 3 p.m. British time on Tuesday.
Hipper reported: "I Scouting Group was therefore no longer of any value for a serious engagement, and was consequently directed to return to harbour by the Commander-in-Chief, while he himself determined to await developments off Horns Reef with the battlefleet".
A reserve unit commanded by Lieutenant Commander Leighton Bracegirdle, it supported the British at Suvla Bay during the Gallipoli Campaign by constructing piers and harbours in the bay.
The fleet was too large to anchor in Alexandria harbour and instead Bonaparte ordered its commander, Vice-Admiral François-Paul Brueys D'Aigalliers to take up station in Aboukir Bay.
After a fierce battle in the harbour, Adm. Horatio Nelson, ignoring orders to withdraw from the fleet commander, Sir Hyde Parker, instead continued to destroy most of the Danish fleet.
