The conflict in Ukraine's separatist east, between Russian-backed militias and Ukrainian forces, flared in recent days with at least seven soldiers killed in renewed clashes.
Pro-Russian separatists killed seven Ukrainian soldiers in fighting on the weekend, Ukraine's military said on Monday. The outbreak of fighting in the east of the country is the deadliest since mid-December.
The clashes, between Ukraine's military and pro-Russian separatists, come as US President Donald Trump calls for better relations between the US and Moscow. The call has alarmed Kiev.
Ukrainian military spokesman Oleksandr Motuzyanyk said separatists backed by Moscow began attacking government positions in the eastern frontline town of Avdiyivka on Sunday.
Five soldiers were killed and nine wounded on Sunday and two more were killed on Monday, authorities said.
The separatists countered on Monday that Ukrainian shelling had killed a woman and wounded three other civilians in the rebel-held town of Makiyivka, south of Avdiyivka.
Ukraine and NATO accuse the Kremlin of supporting the separatists with troops and weapons. Moscow denies it.
The US and EU have imposed sanctions on Russia over the conflict, as well as for its annexation of Crimea.
Ukraine wants the international community to maintain pressure on Russia. The US president has spoken of possibly lifting sanctions imposed by his predecessor, Barack Obama.
Both sides accuse the other of violating a two-year-old ceasefire on a near-daily basis.
Close to 10,000 people have been killed since fighting between Ukrainian troops and rebels seeking independence from Kiev first erupted in April 2014, according to UN figures.
TRT World spoke with Alexander Hug, the principal deputy chief monitor of the Organization for Security and Cooperation in Europe's (OSCE) special monitoring mission in Ukraine.