The accord also eases concerns that a new gas war could disrupt winter energy supplies to EU states.
Despite Russia's new military exercises, Ukraine shows no sign of backing down.
Five Islamist militants were arrested in another security scare weeks before the Winter Olympics.
This is President Vladimir Putin's latest latest bid to burnish Russia's images ahead of the Games.
The arrests come after two deadly attacks raised security fears ahead of the Winter Olympics.
Two seperate terrorist attacks in Volgograd have left at least 33 people dead and over 100 injured.
The former oil tycoon was recently pardoned by Russian President Vladimir Putin after 10 years in jail.
