In eastern Ukraine, where the heaviest fighting is taking place, four people were killed and at least 10 others injured after Russian troops targeted air strikes, missiles and artillery shelling on several cities including Severodonetsk and Sloviansk, a statement from Ukraine’s Joint Forces Task Force said.

Read here Russians in the Luhansk region killed French journalist

In Luhansk and Donetsk, Russian troops shelled 21 areas on Tuesday, and destroyed 46 "civil objects," the statement said.

A separate update from the General Staff of the Armed Forces of Ukraine said Russia is "focusing their efforts on conducting offensive operations" in the Donetsk area, with the support of the air force, and is firing "along the line of contact from mortars, artillery and multiple rocket launchers" in order to "inflict losses and deplete the personnel of our troops."

In Lyman, 60 kilometers (37 miles) west of Severodonetsk, "the fighting continues." Further south in Bakhmut, Russia is "trying to oust units of our troops from their positions," the military said.

The regional military-civilian administration also said that shelling continued all night on positions around Avdiivka, north of Donetsk city, and on Wednesday morning there was shelling of the old part of the city, and the area of ​​the Avdiivka Coke Plant.