One Ukrainian soldier has been killed and four wounded in attacks over the past 24 hours by Russia-backed separatists in the east of the country.
Speaking to reporters on July 1, military spokesman Andriy Lysenko did not disclose further details on the fresh casualties.
The conflict in eastern Ukraine has killed more than 9,300 people since April 2014 and NATO warned last week that the internationally monitored cease-fire there was barely holding.
Under the cease-fire agreement reached last year in Minsk, the Belarusian capital, both the separatists and Ukrainian government forces pledged to pull back heavy weaponry as well as take other steps toward a peace settlement.
In a statement on June 29, Ivan Simonovic, head of the UN Human Rights chief's office in New York, warned of a possible "reescalation of wide-scale hostilities if urgent action is not taken to separate sides and remove heavy weaponry."