Ukrainian government sources said its troops and pro-Russian separatists were locked in fierce fighting in the east of Ukraine.
This comes after rebels rejected a cease fire proposed under a blueprint for peace by President Petro Poroshenko.
Military sources say Ukrainian forces had leafleted rebel areas giving them an ultimatum to lay down their weapons.
Up to 4,000 separatists could be involved in the fighting, according to reports.
Meanwhile NATO’s Secretary General said at least a few thousand more troops are at Ukraine’s eastern border, a build-up he called, “a regrettable step backwards.”
Russia maintains there is a humanitarian crisis on its border, while Ukraine denies there’s a flood of fleeing refugees.
Gianni Magazzeni, Chief of the Americas, Europe, and Central Asia Branch at the UNJ Office of the High Commissioner for Human Rights (OHCHR), in Geneva said: “This situation results in multiple human rights challenges for the people that are caught in the crossfire or even the larger populations within this pocket of territories.
“But it’s also a question of a total breakdown in law and order, the inability to get protection when it comes to ill treatment, detention, abductions and possible also torture and executions”
Ukraine’s parliament has confirmed its next foreign minister will be current ambassador to Germany Pavlo Klimkin.
President Petro Poroshenko’s candidates for central bank chief and general prosecutor were given an unusually high level of support by MPs.