German Chancellor Angela Merkel Monday called on Europe to maintain sanctions pressure on Russia despite a decline in violence in eastern Ukraine, urging Western unity amid Russian efforts to reinvigorate ties with sanctions skeptics such as Italy and Cyprus.

Ms. Merkel, speaking after meeting with Ukrainian President Petro Poroshenko in Berlin, said a full cease-fire still hasn’t been reached and that pro-Russian separatists were continuing to prevent international monitors from having complete access in the regions they...