Ukraine, U.S. Leaders Speak before Putin Talks

Ukrainian President Petro Poroshenko on Thursday discussed the crisis in his country's east with U.S. President Barack Obama before jetting off for talks with Russia's Vladimir Putin aimed at resolving the conflict.

The two presidents stressed that the battered ceasefire Kiev inked with pro-Moscow rebels in the east "must be strictly maintained and observed by all parties" and discussed the need for Kiev to reestablish control over its border with Russia, the Ukrainian presidency said in a statement.

Poroshenko will hold a breakfast meeting Friday with Putin on the sidelines of an Asia-Europe (ASEM) summit in Milan, that will include several European leaders.

The White House said after the call the Milan meeting "offers a good opportunity for leaders to press President Putin to abide by all aspects of the peace plan, including putting in place an effective mechanism for controlling and monitoring the border between Russia and eastern Ukraine."

Ukraine's forces have battled the insurgency since April and accuse Moscow of sending support and regular troops across the border to destabilize Kiev's new pro-Western leadership.

Kiev signed a ceasefire agreement with the separatists on September 5 and a memorandum several weeks later to create a demilitarized zone and end hostilities which have killed over 3,600 people.

Often deadly clashes have continued on a near-daily basis despite the truce, with the sides blaming one another, prompting Western leaders to step in.

U.S. Secretary of State John Kerry earlier this week stressed that "shooting around Donetsk airport and other parts of eastern Ukraine has to stop" and Russian fighters be withdrawn.

Putin on Wednesday lashed out at the United States in an interview with Serbian daily Politika, saying Washington is attempting to "blackmail" Moscow with sanctions and reminding that "discord between large nuclear powers" can lead to global instability.

The EU and U.S. have slapped the toughest sanctions on Russia since the end of the Cold War over its meddling in Ukraine as the crisis has sent East-West tensions soaring.

The Ukrainian leader will also hold bilateral talks in Milan with German Chancellor Angela Merkel on Thursday or Friday, and will also meet European Commission chief Jose Manuel Barroso and EU head Herman Van Rompuy, spokesman Svyatoslav Tsegolko said.