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

Vladimir Putin, wearing a beige pantsuit, climbed into a three-seat submersible craft on Tuesday 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 meters to see the remains of the Byzantine trading ship, which he said dated to the 9th or 10th century.

On previous trips deep underwater, 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.

Speaking by radio to Russian Prime Minister Dmitry Medvedev while still under water, Putin said he hoped the trading ship would shed light on Russia's development and show "how deep our historical roots are".

He told Medvedev he should have come along.

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

Off the vessel, Putin was greeted by Medvedev, who gave him a hug, and also by his chief of staff and defense minister.

They were among the many Russian officials who accompanied him on this week's trip to Crimea.

Asked by a reporter whether it was wise to spend money on such ventures when Russia's economy is struggling through a painful recession, 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".

AP - AFP