Another summer, another trip to the bottom of a sea for Russia's adventure-loving president.

Vladimir Putin climbed into a three-seat submersible craft to check out an ancient sunken ship found recently in the Black Sea off the coast of Crimea - the peninsula annexed by Russia last year from Ukraine.

He descended 83 metres (272ft) to see the remains of the Byzantine trading ship, which he said dated back to the 9th or 10th century.

On previous trips deep underwater, Mr Putin has explored the Gulf of Finland and Lake Baikal in submersibles. He also went scuba diving in the Kerch Strait that connects the Black Sea to the Sea of Azov, where he brought up fragments of ancient Greek jugs, or amphorae, that his spokesman later admitted had been planted.

Speaking by radio to prime minister Dmitry Medvedev while still under water, Mr Putin said he hoped the trading ship would shed light on Russia's development and show “how deep our historical roots are”.

“It's great, there are lots of objects, amphorae scattered around,” Mr Putin said. He ended the chat with a casual “Big hug!”

Off the vessel, Mr Putin was greeted by Mr Medvedev, who did give him a hug, and also by his chief of staff and defence minister. They were among the many Russian officials who accompanied him on this week's trip to Crimea.

The Russian president was part of an expedition near Sevastopol, Crimea

Pressed by a reporter as to whether it was wise to spend money on such ventures when Russia's economy is struggling through a painful recession, Mr Putin said his dive should help attract publicity and donors to the important work being done by the Russian Geographical Society to study “how our state was built, including in this region”.