German Chancellor Angela Merkel said Saturday it's uncertain whether a flurry of diplomacy aimed at calming the crisis in Ukraine will succeed, and warned that there are no guarantees any deal would stick.

"This conflict cannot be resolved by military means," Merkel said at the Munich Security Conference on Saturday. "It is all the more important now to set out substantial steps that serve to fill with life the Minsk agreement."

The German diplomat said that "it is uncertain whether they [the talks] will be successful, but it is from my point of view and that of the French president in any case worth making this attempt."

The German leader acknowledged that experience to date of agreements being violated on the ground has been disillusioning.

Asked whether there are any guarantees a new agreement won't suffer the same fate, she replied that "there are no theoretical guarantees."

"After such experiences, I am very cautious with guarantees," she said. "The guarantee can only be keeping to what has been agreed ... but the answer can't be not to make any more agreements. Of course we have to try again and again, at least I think so, "Merkel stressed.