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BERLIN, July 4 (Xinhua) -- The leaders of Germany, French and Ukraine held a telephone conversation on Friday to discuss developments in Ukraine, German government spokesman Steffen Seibert said in a statement.
German Chancellor Angela Merkel, French President Francois Hollande and Ukrainian President Petro Poroshenko agreed that a bilateral ceasefire and a common approach by Ukraine and Russia to secure their border are preconditions to stabilize the situation in Ukraine.
The three leaders called on Russia to exert its influence to help achieve the goals.
Poroshenko stressed his determination to push ahead with implementation of his peace plan during a ceasefire. He also pledged to do everything possible to avoid civilian casualties as long as fighting continues in his country.
Poroshenko on Tuesday ended a 10-day truce in eastern Ukraine and the Ukrainian military resumed its offensive in the states of Donetsk and Lugansk by launching air raids on rebel targets.
At the invitation of German Foreign Minister Frank-Walter Steinmeier, the foreign ministers of France, Russia and Ukraine met Wednesday in Berlin to discuss ways of calming the situation in Ukraine.
Steinmeier and his counterparts Laurent Fabius from France, Sergey Lavrov from Russia and Pavlo Klimkin from Ukraine agreed that a sustainable ceasefire should be agreed upon swiftly and observed by all concerned to put an end to violence in eastern Ukraine.
The four ministers also urged the contact group to resume with the goal of reaching an unconditional and mutually agreed sustainable ceasefire no later than July 5, which should be monitored by the OSCE Special Monitoring Mission in Ukraine in conformity with its mandate.
Merkel and U.S. President Barack Obama on Thursday voiced support for a sustainable ceasefire in eastern Ukraine through diplomatic means, and threatened additional sanctions should Russia fail to take immediate de-escalatory steps, according to a statement from the White House.