“As the stakes are now so high, the Secretary-General is seriously concerned that the situation could quickly spin out of control with consequences we cannot predict,” the spokesperson said in a statement.

According to media reports, tensions in Ukraine escalated sharply today, with Russia embarking on new military drills near the border after Ukrainian forces said they killed five pro-Russian militants.

The United Nations chief stressed “in the strongest terms” the necessity for all parties to honour their commitments under the Geneva Statement, which was issued last week following a meeting between the United States, the European Union, Ukraine, and Russia.

At that meeting, participants agreed to a series of steps to de-escalate tensions in eastern Ukraine that reportedly include demobilizing militias and vacating seized Government buildings.

“Military action must be avoided at all costs,” Mr. Ban’s spokesperson said.

“The Secretary-General calls on all sides to immediately refrain from violence, intimidation or provocative actions and find a way forward toward de-escalation.”