Three Ukrainian soldiers have been killed and two others wounded when their car hit a mine in the restive east of the country.
Reports from Lugansk said the deaths occurred after a military vehicle carrying troops from Ukraine's 80th brigade hit the mine about 75 kilometers (45 miles) west of the Russian border.
A military spokesman in Kiev said another three government troops were wounded in separate exchanges of fire near the front line with pro-Russia forces in Lugansk and Donetsk regions.
They provided no other details and said the toll was only preliminary as an investigation was underway.
The pro-Russia forces, however, said Kiev soldiers had wounded two of their fighters in an overnight attack on the forces de facto capital, Donetsk.
Two civilians were also reported killed on Saturday after one of them set off a trip wire in the Lugansk province.
Ukraine's emergencies ministry has reported special teams cleared the ravaged war zone of more than 44,000 explosive devices by mid-October 2014.
But the two sides and foreign monitors are struggling to estimate how many such indiscriminate weapons remain.
Meanwhile, German Foreign Minister Frank-Walter Steinmeier told the UN Security Council on Monday he remained "deeply concerned over the continuing violations of the ceasefire" agreed in February 2015.
A series of periodic truce deals that followed have been able to curb the violence but not put a full end to a 23-month conflict that has claimed more than 9,000 lives.
Kiev and its Western allies claim Moscow is orchestrating the crisis by supporting Ukraine’s pro-Russia forces with Russian troops and weapons.
Russia denies the allegations and says the United States had triggered the street protests that toppled Ukraine's pro-Russia president in February 2014 and led to the current conflict in east Ukraine.