Russia has deployed a reconnaissance ship to the eastern Mediterranean in a bid to "to gather current information in the area of the escalating conflict", a military source told Interfax news agency.
The ship is understood to have left the naval base in the Ukrainian Black Sea port of Sevastopol late on Sunday.
The Defence Ministry declined to comment on the reports.
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A cloudy afternoon for many areas across the UK. The winds also strong with gusts on western coasts of Scotland. Temperatures remain mild.