Russia has been building up its forces on the Ukrainian border steadily over the past few weeks and now has an estimated 10-12,000 troops in the area, a Nato military officer said.
Russia had withdrawn the majority of the 40,000 troops it had on the border earlier this year, and there were fewer than 1,000 by the middle of June. Speaking on the condition of anonymity, the officer told Reuters:
"Our current assessment is that between 10,000 and 12,000 troops are now in the area ... In the last week alone, we have seen several units moving into the border region."
More top news
Some dogs have been at the Battersea Dogs and Cats Home for more than a year. Can you make their Christmas and give them a new home?
Selfless Donna Wood from Staffordshire has left her husband and children at home so she can help save lives in Sierra Leone.
From Sierra Leone to Cyprus, 8,500 Christmas boxes were sent out to every serviceman and woman from the UK.