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KIEV, June 16 (Reuters) - President Petro Poroshenko called on Monday for a truce in east Ukraine, where his government faces a rebellion by pro-Russian separatists, to provide time to seek agreement on a peace plan.
In a statement to security chiefs, Poroshenko said he had set government forces the task of regaining full control of Ukraine's border with Russia this week.
Once the frontier was secure, he said, a temporary ceasefire should be observed and efforts made to agree on a peace plan.
"Declaring a ceasefire while the border is open would be irresponsible," he said.
The separatists rose up against central rule in April following the removal of a president in Kiev who was sympathetic to Moscow, and Russia's subsequent annexation of the Black Sea peninsula of Crimea. Scores of government troops, rebels and civilians have been killed in fighting since then.
Since he was sworn in on June 7, Poroshenko has been trying to win agreement for peace proposals, few details of which have been published. His efforts have included talks with a Russian envoy and a phone call with President Vladimir Putin.
Kiev and the West have accused Russia of arming the rebels in east Ukraine but Moscow denies the accusations.
Poroshenko said his proposals included constitutional changes to allow more decentralisation of power, a demand by many people in eastern Ukraine. He did not say how long the truce he was proposing should last.
(Reporting by Natalia Zinets, Editing by Timothy Heritage and Kevin Liffey)