OSCE

U.S. paramedic Joseph Stone is the first casualty of an international monitoring mission in eastern Ukraine.

The OSCE monitor died in a landmine explosion in the region where Russian-backed rebels are fighting Ukrainian forces.

Organization for Security and Cooperation in Europe also fell victim to a cyber hack that used tools attributed to a Russian group.

International observers claim hostilities have increased by 40 percent in a week.

Most airspace over eastern Ukraine remains off limits to civilian air traffic.

Outside observers have monitored U.S. elections since 2002.

Kiev claims separatist rebels using heavy weapons banned under ceasefire as one killed and six wounded in clashes.

Poroshenko says that he believes this will be most efficient guarantor of security.

Some forces are withdrawn from Debaltseve but senior Ukrainian police official says fighting will continue in the town.

The peace deal, which only came into force this weekend, already looks under threat.