Russia fears the resumption of hostilities in Ukraine which would pose a threat to the country's security, Kremlin spokesman Dmitry Peskov said on Friday.
Recent developments in southeast Ukraine show that the country's authorities have not given up ideas of implementing a military solution to the problem, Peskov told reporters in Moscow.
The escalation in Ukraine pushes Russia to take measures to ensure its security, he said.
"The growth of tension, the escalation of tension in the southeast of Ukraine determines the measures that Russia is taking to ensure its security. Russia has not threatened and does not threaten any country in the world," he said.
Asked about German Chancellor Angela Merkel's demand to withdraw the Russian military from Ukraine's border, Peskov said Russia is free to move its armed forces on its territory at its own discretion.
He added that Ukraine is potentially turning into a very unstable region, and any country that has an unstable, dangerous, explosive region near its borders will take measures to ensure its security.
In a separate statement, Russian Foreign Ministry spokeswoman Maria Zakharova called on Kyiv to implement the Minsk Agreement on peaceful settlement in Donbas.
"So far, the Ukrainian authorities have avoided taking concrete steps towards a peaceful settlement of the situation in the Donbas and continue to ignore the letter and spirit of the Minsk package of measures, including the need to coordinate various aspects of a peaceful settlement with representatives of Donetsk and Luhansk in the course of a direct dialogue.
"Increasingly, Kiev is promoting slogans about ‘a Russian threat,’ while it is the Ukrainian troops who are increasing their presence near the contact line, firing, from which civilians suffer," she said.
Zakharova pointed out that since 2014, a monitor group from the Organization for Security and Cooperation in Europe (OSCE) has worked at the section of the Russian - Ukrainian border that is not currently controlled by Ukraine's government.
For the time the group has been working, it has not registered any military equipment of troops transfer from Russia to Ukraine despite Ukraine's allegations, she said.
In recent days, the OSCE Special Monitoring Mission to Ukraine (SMM) has reported an increasing number of violations and firings in the Donetsk region.
It also complained about the impossibility to use a long-range unmanned aerial vehicle (UAV) in government-controlled Stepanivka, Donetsk region, due to dual GPS signal interference, assessed as jamming and restrictions of movement on both sides.
On Thursday, Ukrainian President Volodymyr Zelensky visited positions of troops on the front line in Donbas.
He spoke with the military who told him about the situation on the line of contact, thanked them for their service and presented state awards and gifts.
On Friday, Zelensky continued his visit to the frontline and walked along forward positions.
"Every day you show patriotism and dedication in defending Ukraine. Take care of yourself," he said to soldiers.
The trip of the Ukrainian leader to Donbas took place during an escalation on the line of contact. Kyiv and separatists accuse each other of violating the truce. Ukraine also accuses Russia of pulling troops to the border. Moscow says it is a response to "Kiev's provocative actions."
By Elena Teslova in Moscow