Four people died and 10 were hospitalised as a series of forest fires swept through part of the eastern Ukrainian region of Luhansk on Thursday.
The fires threatened 22 settlements and engulfed an area of about 18,000 hectares, the service said in a statement, adding that 120 people were evacuated.
Local authorities said there were a total of 146 fires, 82 of them were extinguished.
Most of the fires are located near the area controlled by pro-Russian separatists and local Ukrainian authorities have stated that the fires may have been caused by shelling from the separatists.
The Ukrainian presidential office called on law enforcement bodies to find the cause of the fires.
"The reasons for such a large-scale spread of fire must be clearly established," the office said in a statement.
"We also take into account the information about provocative shelling that could have been carried out from the temporarily occupied territory... and could have caused at least some of these fires in such weather conditions," it added.