Western leaders have criticised Russia for its "destabilising" influence on the crisis in eastern Ukraine, at the opening of the NATO summit in Newport, Wales.
British Prime Minister David Cameron said Russian troops were in Ukraine illegally.
World leaders said pressure on Russia would be increased if it did not change course. Russia denies claims that it arms rebels and has troops in Ukraine and in recent days Russian President Vladimir Putin has been talking about ceasefire conditions.
David Cameron said the summit must address many challenges including the threat from the Islamic State terrorist group in Northern Iraq.
IN: Russian troops..
OUT;..achieved there."
DUR: 29