U.S. and European leaders have agreed to extend sanctions against Russia. This would delay the existing sanctions deadline of just a few days after Donald Trump takes office in January. 

Barack Obama's parting words to his closest foreign partner were: "Good luck."

The outgoing U.S. president says a Donald Trump White House will still value the fundamentals of the Trans- Atlantic Alliance.

But neither leader hides that the relationship may well look rather different.

For one thing -- the president-elect has promised to thaw relations between Washington and Moscow.

That is not yet in his power though.

European and U.S. leaders have agreed to extend sanctions over Russia's annexation of Crimea.

"We talked about sanctions in the context of Ukraine. The U.S. president said, and we all agreed, that we stand together as the united nations of the European Union. We want to make progress on the Minsk agreement. Up until now, there has been no visible progress to be honest with you," said Angela Merkel. German chancellor.

Further punishment over Syria is also in their sites.

Officials on both sides of the Atlantic accuse Vladimir Putin of pushing for advantage on the ground ahead of the American transition   despite mass civilian casualties.

"On Syria, of course looking at Aleppo, we were united in our condemnation of the atrocities that are taking place there - we agreed the need to keep up the pressure on Russia, including the possibility of sanctions, including on those who breach international humanitarian law," said British PM Theresa May.

Such measures have been central to the Chancellor's arsenal - to date, with U.S. support.

"The sanctions regime is very important for the west's position towards Russia - and if it should come to that: that the new U.S. president would change his position on the sanctions regime, I think a lot of other European nations could also shift to the U.S. policy and that would make it very hard for Chancellor Merkel to keep up support in Germany as well," said Sebastian Feyock, Transatlantic Relations Program, German Council on Foreign Relations.

As Obama departs - Europe is still holding its breath. Much about what's to come seems to remain an educated guess - even at the highest level.

The president-elect continues to wrongfoot the establishment: arranging a meeting with Japanese Prime Minister Shinzo Abe without the full involvement of the U.S. State Department. Straying from protocol with a casual invite to British Prime Minister Theresa May to "let him know" if she happens to be coming to America. But leaders here have shown cautious optimism - that beneath the unpredictable and unorthodox Donald Trump - will be a president of some continuity.