Developments in Ukraine - Sept. 1, 2014

Ukrainian President Petro Poroshenko watches cadets as they march during Knowledge Day celebrations in Kyiv, Sept. 1, 2014.

Ukrainian servicemen ride in an armored vehicle in Kramatorsk, Sept. 1, 2014.

Pro-Russian rebel leaders from Eastern Ukraine Andrei Purgin, left, and Alexey Karyakin walk in Minsk, Belarus, Sept. 1, 2014.

Russia and Ukraine will be the top story this week when NATO heads of state attend the NATO summit in Wales, starting Wednesday. NATO Secretary General Anders Fogh Rasmussen addresses the media ahead of the NATO summit in Wales, at the Residence Palace in

First-graders attend a festive ceremony to mark the start of another school year in Slovyansk, Ukraine, Sept. 1, 2014.

Schoolgirls talk during morning assembly in a school in the southern coastal town of Mariupol, Ukraine, Sept. 1, 2014.

A child looks out of a train window as people who have fled from fighting in the eastern regions of Ukraine arrive at a railway station in Krasnoyarsk, Russia, on their way to a temporary accommodation in local cities and settlements in Siberia, Sept. 1,

A Ukrainian military helicopter flies above a military base in the eastern Ukrainian town of Kramatorsk, Sept. 1, 2014.

Russian President Vladimir Putin listens during a meeting on development of the Russian Far East issues in Yakutsk, Russia, Sept. 1, 2014.

FILE - Russian Foreign Minister Sergey Lavrov said talks meant to ease the Ukraine crisis being held in Belarus on Monday should focus on an immediate, unconditional cease-fire between the Kyiv government and separatists in eastern Ukraine.