Canada announced economic sanctions and travel bans Saturday on 11 Russians and Ukrainians, as well as a Crimean oil company, saying they facilitated the violation of Ukrainian sovereignty.

The move came as a unilateral ceasefire in the ex-Soviet state hung in the balance with clashes engulfing the separatist east and Russian President Vladimir Putin putting troops on "full combat alert."

"Russia's illegal occupation of the Crimean peninsula in Ukraine and provocative military activity remains a serious concern to the international community," Prime Minister Stephen Harper said in a statement.

"The measures we are announcing today against additional Russian and Ukrainian individuals and an entity that have facilitated the violation of Ukrainian sovereignty and territorial sovereignty will continue to increase economic pressure on those responsible for the crisis in Ukraine."

The company in question is Feodosia Enterprise.

Ukrainian President Petro Poroshenko ordered his forces to hold fire for a week on Friday as part of a broader peace plan to end the worst East-west standoff since the Cold War.

"Canada also supports President Poroshenko's peace plan," Harper said, vowing that Ottowa would "continue to work with our allies to apply pressure against Russia."

The sanctions follow similar penalties imposed recently in coordination with the United States and the European Union.

"We continue to monitor the situation and we are ready for further actions if necessary," Harper said.