New Ukrainian leader Petro Poroshenko said the violence that has rocked the former Soviet republic's easternmost regions must end this week as peace talks began involving an envoy of Russian President Vladimir Putin.

Poroshenko, who took the oath of office Saturday, said negotiations should be held on a daily basis. Sunday's three- way talks in Kiev included Ukrainian Ambassador to Germany Pavlo Klimkin, Russian Ambassador to Ukraine Mikhail Zurabov and Heidi Tagliavini, a special representative of the Organization for Security and Co-operation in Europe.

"We must stop the violence this week," Poroshenko said in a statement on his website. "For me, every day when people die, every day when Ukraine pays such a high price, is unacceptable."