Russian naval forces continue to blockade the Ukrainian coast on the Black Sea and Sea of Azov, preventing resupply by sea, British military intelligence said on Sunday.
Russia retains the capability to attempt an amphibious landing, but such an operation is likely to be increasingly high risk due to the time Ukrainian forces have had to prepare, the Ministry of Defence tweeted in a regular bulletin.
"Mines within the Black Sea pose a serious risk to maritime activity," it said.