U.N. Chief 'Alarmed' by Upsurge in Ukraine Fighting

U.N. Secretary-General Ban Ki-moon on Monday expressed serious alarm over the upsurge in fighting in Ukraine and called for urgent steps to de-escalate the violence.

Fierce clashes in east Ukraine killed at least 10 people in the past 24 hours, government and rebel officials said Monday, as Russia warned that Kiev could be preparing for a fresh offensive.

Ban said he was "seriously alarmed by the recent escalation of violence in eastern Ukraine" and that "continued ceasefire violations and the resulting loss of life are unacceptable."

He called on "all sides to take urgent steps to de-escalate the current situation and prevent a spiral of violence that will lead to more deaths, human suffering and destruction of infrastructure and negatively affect regional stability."

Kiev's pro-Western forces in recent days have been fighting the rebels for control of a strategic highway linking Donetsk with Mariupol -- the last major government-held city in the region.

The fighting has been the heaviest since the signing in February of a truce deal agreed by the leaders of France, Germany, Russia and Ukraine.

Ban cited reports that monitors from the European OSCE group were being harassed and urged all parties to respect their role.

Ukraine and the West accuse Russia of pouring troops and weapons across the border to fuel a conflict that has claimed more than 6,800 lives since April 2014 and has driven 1.4 million people from their homes.