A Russian television cameraman was killed overnight during shooting in east Ukraine which Moscow said undermined faith in Kyiv's desire to resolve weeks of conflict peacefully.
Anatoly Klyan, 68, worked for state-owned Channel One and was the third Russian journalist killed since pro-Russian separatists began an uprising against central rule in April.
Klyan was shot in the stomach while accompanying a group of soldiers' mothers being driven to a pro-Kyiv military unit "to meet their sons and take them home," the station said on its website.
The bus carrying the mothers and journalists withdrew after coming under fire as it approached the base. Klyan died when a group of people came under further automatic rifle fire after leaving the bus, Channel One said.
There was no immediate comment from the Ukrainian military forces or the government in Kyiv.
Moscow protested against the killing and renewed calls for an end to a military operation launched by government forces in the eastern regions of Donetsk and Luhansk, where separatists have seized state buildings and weapons arsenals.
"The death of a Russian journalist again convincingly demonstrates that Ukrainian forces clearly do not want a de-escalation of the conflict in the east of the country," the Russian Foreign Ministry said in a statement.
"They are hampering the already fragile ceasefire," it said.
On June 17, a Russian correspondent and a sound engineer for state television were killed by mortar fire in clashes near the eastern city of Luhansk.
Sporadic violence has continued in eastern Ukraine despite a ceasefire declared by Ukrainian President Petro Poroshenko on June 20 to allow for peace talks with the rebels. The ceasefire is due to expire on Monday evening.