Kiev’s attempt to solve the Ukrainian crisis with military force is a blunder, which may affect the country’s territorial integrity, Russia’s foreign deputy minister said. On Sunday, Kiev renewed its assault in southeast Ukraine.

"It's the biggest, even strategic mistake of the Ukrainian authorities to bank on a military solution to the crisis in Ukrainian society and to all of southeast Ukraine's problems. This can lead to irreversible consequences for Ukrainian statehood," Grigory Karasin, Russia’s deputy foreign minister, was quoted as saying by Interfax news agency.

Earlier, in a statement, the Russian Foreign Ministry urged Kiev to take steps to pull its heavy weapons out of Eastern Ukraine, saying that their militia opponents had already signed a roadmap for it.

An arms pullout is a key point in the so-called Minsk agreement, a roadmap to deescalating the situation. However it was never fully implemented after the Russia and OSCE-brokered deal between the government in Kiev and their opponents was penned in September 2014.

“If Kiev truly prepared to pull back heavy weapons as would the militia do… this should lead to practical steps on the ground, especially considering that the leaders of [the self-proclaimed Donetsk and Lugansk People’s Republics] have already signed a roadmap for it,” the Russian Foreign Ministry said in a statement Monday.

The rebels did sign the roadmap, but a disagreement remains on where the disengagement line separating the warring parties should exactly be. On Sunday Moscow said it is trying to do what it can to make the militia commanders agree to the terms that the Ukrainian government is insisting on.

A shaky balance established by the Minsk agreement was constantly mired by mutual shillings and clashes for the contested area of the devastated Donetsk International Airport, a position within the range of artillery fire from the city of Donetsk. The local militia have for months accused Ukrainian troops stationed at the site of violating the ceasefire and shelling civilian areas. Kiev insisted that the anti-Kiev forces themselves should be blamed and accused them of launching regular attacks on their positions.

READ MORE: Donetsk shelled as Kiev ‘orders massive fire’ on militia-held E. Ukraine

Now both parties claim that they are in control of the site, with verification of either claim being difficult to prove.

The two sides also give vastly differing casualty numbers for the day of intensive clashes on Sunday. Kiev reported losing three soldiers killed and 66 wounded. The rebels estimated that as many as 200 of Kiev’s soldiers were killed over the day.

Another mark of escalating violence in Eastern Ukraine is the deployment of military aircraft reported by head of the Donetsk Republic Aleksandr Zakharchenko and later confirmed by the Russian head of a joint ceasefire monitoring group. The bomber jets have been used “for the first time after a long delay”, Colonel Andrey Kozlov stressed.

Kiev denied using aviation in its Sunday offensive. The only aircraft involved were “ready to evacuate the wounded” the spokesman for Kiev’s military campaign, Andrey Lysenko, said Monday.

The renewed hostilities disrupted the lives of civilians living in the region. In the town of Makeevka, which suffered heavily from artillery fire and was reportedly bombed by the Ukrainian air force on Sunday, all public gatherings were canceled. School and college students in all Donetsk region cities were told to stay at home on Monday.

According to militia count, at least nine civilians were killed and 44 injured in Donetsk alone on Sunday, as it endured some 50 artillery barrages.

The surge of violence was marked with concern by various international organizations, who called on all parties to stop it and protect the civilian population.

“We once again call on all parties to refrain from harming civilians and to comply with international humanitarian law,” The International Committee of the Red Cross told RT in a statement. “We remind them that indiscriminate attacks are prohibited. The tragic death of civilians in a bus near Volnovakha in the Donetsk region on 13 January is one of the many incidents that highlight the unacceptable situation in which ordinary people find themselves.”

READ MORE: 'Je suis Volnovakha': Charlie-copycat slogan at pro-govt rally as Kiev shells E. Ukraine

Meanwhile, the Ukrainian government doesn’t hide its intention to bring back the unruly territories, and apparently it intends to do it through military force.

“We won’t give away an inch of Ukrainian land and we will return Donbass,” Ukrainian President Petro Poroshenko pledged on Sunday before a crowd in Kiev.

READ MORE: Poroshenko rejected Putin’s artillery withdrawal plan, began assault - Kremlin

The leaders of the self-proclaimed republics accused Kiev of deception, saying the only reason it agreed to the Minsk ceasefire was to build up its troops and stockpile weapons before resuming the crackdown.

Kiev insists that it didn’t violate the agreement and that the offensive was limited to the border line and the militia fighters holding positions there. The Ukrainian military would not explain why the supposedly limited operation includes the shelling of residential areas in Donetsk and other rebel-held cities.

One of the latest incidents happened on Monday, when an artillery shell hit a Donetsk hospital injuring a surgeon and giving concussion to several elderly patients. The explosion also broke windows and damaged heating in the building, according to the city’s emergencies services.