BERLIN (REUTERS) - German Chancellor Olaf Scholz and US President Joe Biden agree the situation in Ukraine must be assessed as "extremely serious" as there is still a risk of further Russian military aggression, German government spokesperson Steffen Hebestreit said on Wednesday (Feb 16).

"Maximum vigilance" is needed as there has been no significant withdrawal of Russian troops so far, Hebestreit said in a statement after Scholz's phone call with Biden following the German chancellor's trips to Kyiv and Moscow.

At the same time, both leaders welcomed Russian President Vladimir Putin's statement that diplomatic efforts should continue, the spokesperson said.

Scholz and Biden agreed it is important to move towards the implementation of the Minsk peace agreements negotiated by Russia, Ukraine, France and Germany in 2015 and to make progress in the Normandy format - a grouping of envoys from those countries that has met periodically since the 2014 Russian annexation of Crimea - with the support of Germany and France, Hebestreit said.