David Cameron is "gravely concerned" at reports of Russian military vehicles crossing into Ukraine, his spokesperson said.
After speaking to Ukraine's President Petro Poroshenko, the Prime Minister said Russia must not use its humanitarian aid convoy as a pretext for provocation and asked Russia to "demonstrate willingness to find a peaceful solution to conflict in Ukraine."
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Early low cloud will gradually retreat to North Sea coasts to leave many with a fine day, particularly in the west.
An elephant calf had to be rescued in Sri Lanka after becoming trapped in a drain.
According to local reports, the repairman had failed to disconnect the power to the escalator before getting to work.