Ukraine's military says two of its servicemen have been killed and four others wounded in separatist attacks in the country's east.
Military spokesman Andriy Lysenko said on May 18 that the casualties occurred over the past day.
The announcement came after the Ukrainian military claimed to have captured two Russian soldiers fighting alongside pro-Russian rebels in eastern Ukraine.
More than 6,000 people have been killed since clashes began in April 2014 between Ukrainian government forces and separatists in the country's east.
The eastern Donetsk and Luhansk regions continue to be embroiled in sporadic fighting despite a cease-fire sealed in mid-February and brokered by Germany and France.