Russian forces have been digging defensive fortifications and trenches that experts say would be difficult and costly to overcome.
Experts say that those defences are likely to make any such effort difficult and bloody.
Russia annexed Crimea in 2014, eight years before launching a full-scale invasion of Ukraine in February 2022. As the war grinds on for more than a year, Ukraine's political and military leadership has made it clear that it defines victory as reclaiming its 1991 borders, which Russia had recognised. The United Nations and all of Ukraine's Western allies also recognise those borders, which include Crimea.
Comment: There's little chance that Ukraine will retake Crimea because, as noted above, it's of utmost importance to Russia, and its people, and as Putin has said, in this conflict, Russia has hardly gotten started.