Moscow is "deeply concerned" about the recent situation in eastern Ukraine, Kremlin spokesman Dmitry Peskov said Wednesday.
"Naturally, Moscow is closely monitoring (the situation)," Peskov said.
Moscow was deeply concerned about the ongoing shelling of settlements in Donbas, the loss of lives including children, Peskov added.
Russia was closely watching how the situation was developing, and would formulate a reaction depending on the development, RIA Novosti news agency quoted Peskov as saying.
Also on Wednesday, Russian Foreign Minister Sergei Lavrov said Russia had asked the Organization for Security and Cooperation in Europe (OSCE) to establish an objective picture and report who is violating the Minsk agreements.
"The aggravation of military tensions on the line of contact is the most acute problem at the moment," Lavrov said, adding Russia is ready to meet "in any format" with relevant sides to fully implement peaceful agreements reached in Belarusian capital of Minsk in February.
He also noted that working subgroups of the three-party contact group involving Russia, Ukraine and the OSCE made certain progress on Tuesday on withdrawal of weapons and demilitarization of certain locations like Shyrokyno village in Donetsk region.
Ukraine's army said earlier Wednesday that pro-independence rebels in eastern regions have launched a "major offensive" to push deeper into the government-controlled territory, an accusation the rebels denied.
No official information on casualties was immediately available. Local media said fighting near Mariynka, the government-controlled town, which lies 30 kilometers west of the rebel stronghold of Donetsk, resulted in heavy losses from both sides.
The conflict in eastern Ukraine since April 2014 has killed over 6,400 people, according to the latest United Nations estimates.
In an attempt to end the violence, a truce deal was signed on Feb. 12 in Minsk, which covers a comprehensive ceasefire, withdrawal of all heavy weapons from the frontline and creation of a buffer zone between the two warring sides.