The UN Secretary-General Ban Ki-moon was encouraged by "concrete and urgent steps" aimed at de-escalating the Ukraine situation agreed at four-way talks in Geneva on Thursday.

Ban welcomed the initial round of diplomatic negotiations on the crisis in Ukraine in Geneva by top diplomats from Ukraine, Russia, the United States and the European Union, a statement from his spokesperson said.

"He is encouraged that all parties were able to agree on a number of concrete and urgent steps aimed at de-escalating the situation and finding a peaceful resolution to this crisis," it said.

The four-way talks reached an agreement Thursday, calling for an immediate halt of violence in Ukraine and practical steps to de- escalate the tension.

Ban said the situation in Ukraine remains "extremely volatile". He expected all sides to show their serious intention to continue to engage, in a good-faith effort, and to implement the steps laid out in the Geneva Statement, which would contribute to a lasting solution to this crisis.

A new wave of unrest recently erupted in three eastern states of Ukraine, where pro-Russia protesters staged rallies calling for federalism in the country or joining the Russian Federation. Some government buildings were stormed and have been occupied since April 6.

In response to the move, Ukraine launched an "anti-terror" operation, deploying 20 tanks and armored personnel carriers to the eastern region.