BRUSSELS, Dec 10 (Reuters) - The European Union wants Russia to de-escalate the tension it created by amassing troops on the border with Ukraine and the 27-bloc is ready to step up sanctions against Russia should it invade Ukraine, the head of the European Commission said. Speaking at a joint news conference with Germany"s new Chancellor Olaf Scholz, Commission President Ursula von der Leyen said the EU wanted good relations with Russia, but they depended on how Russia would behave. "We want de-escalation and a cessation of all aggression against its (Russia"s) neighbours," von der Leyen told the news conference. "Otherwise, the European Union will look to intensify its sanctions and take other measures across economic and financial sectors, in agreement with our partners," she said. "We want a good relationship with Russia, but it depends first and foremost on the way in which Russia behaves. Russia is taking a threatening stance towards its neighbours and that undermines Europe"s security," she said.