Moscow and Kyiv have traded accusations as fighting escalates in eastern Ukraine and casualties mount.
Russian Deputy Foreign Minister Grigory Karasin on January 19 accused Kyiv of trying to solve the conflict through military force and warned of "irreversible consequences for Ukrainian statehood," as both sides accused each other of ignoring appeals for a cease-fire to be respected.
Ukraine's army said some 700 Russian troops had crossed into the country on the morning of January 19 to support pro-Russian separatists.
The allegation comes as Ukrainian government troops and pro-Russian separatist fighters are battling for the control of the bitterly contested Donetsk airport in eastern Ukraine.
The Ukrainian military claims its troops have retaken almost all the areas of the ruined airport lost to separatists in recent weeks.
But a separatist leader, Aleksandr Zakharchenko, said that "all the Ukrainian Army's attempts to take the airport...have failed."
Military spokesman Andriy Lysenko told reporters on January 19 that three Ukrainian servicemen were killed and 66 wounded in the previous 24 hours, but he would not say how many of those casualties occurred at the airport.
Artillery fire was reported in several areas of the eastern Donetsk and Luhansk regions and a hospital in the city of Donetsk was reportedly hit.
And in the eastern city of Kharkiv, an explosion outside a court on January 19 injured 12 people, according to Vasyl Ostropilets, first deputy police chief of the Kharkiv region.
Markiyan Lubkivsky, an adviser for the state security service SBU, said on his Facebook page the incident was being treated as a "terrorist act."
Kharkiv is a large city in eastern Ukraine, but far away from the conflict zone in the Donetsk and Luhansk regions further to the east.
However, in recent weeks there have been dozens of small bombings across the country, with the epicenters being Kharkiv, Odesa, Mariupol, and Kyiv.
Authorities and most Ukrainians are convinced that the attacks are directly linked to Russia.
Amnesty: Civilians Suffering
Rights watchdog Amnesty International said in a statement on January 19 that the escalation in hostilities in eastern Ukraine since January 18 had resulted in the deaths of numerous civilians, including children, and put civilian lives in great danger.
London-based Amnesty International said pro-Russian separatists used densely populated areas for launching military operations while the Ukrainian troops returned heavy fire into those areas.
Amnesty said rebels fired rockets from residential areas in Donetsk and Horlivka. Artillery fire was returned by Ukrainian troops, killing at least two civilians in Horlivka on January 18, the group said.
Shelling by separatists killed three people and injured 10 others in government-controlled Debaltseve on January 19.
Amnesty urged both parties to stop using populated areas for staging military operations.
In Kyiv, Ukrainian President Petro Poroshenko reiterated he was ready for fresh peace talks, but that Russia would first have to fulfill the agreements to end the separatist conflict signed in Minsk in September 2014.
No Easing Up On EU Sanctions
In Brussels, EU foreign-policy chief Federica Mogherini said the situation on the ground in Ukraine was "much worse than last week," and ruled out relaxing the bloc's sanctions against Russia before Moscow implemented the Minsk agreements.
"Our relations with Russia can only change if and when -- I hope 'when', but at the moment it is 'if' -- commitments that were taken in Minsk are implemented, and let me say that the latest developments on the ground are not encouraging, rather the contrary," Mogherini said on January 19 after a meeting of EU foreign ministers.
Mogherini had earlier suggested in a confidential memo leaked to the media that EU governments could start talking to Russia again about global diplomacy, trade, and other issues if Moscow implemented the Minsk peace agreement to end the separatist conflict.
The United States and European Union have imposed economic sanctions on Russia following Russia's annexation of Crimea last March.
The West also accuses Russia of sending troops and weapons into eastern Ukraine to support the separatists, which Moscow denies.
The EU also pledged to respond to a perceived Russian propaganda campaign, after the issue was raised in a recent letter signed by the foreign ministers of Denmark, Estonia, Lithuania, and Britain.
Mogherini said the EU will work on "concrete steps to be implemented in the coming weeks," adding, however, that the bloc would not engage in counterpropaganda.
And Lithuanian Foreign Minister Linas Linkevicius told RFE/RL that there was "wide support" among his EU counterparts for the need to address Russian propaganda.
Linkevicius said EU institutions will prepare a draft action plan, and "will be able to then discuss concretely what could be done."
With reporting by RFE/RL's Brussels correspondent Rikard Jozwiak, Interfax, AFP, Reuters, and AP