A total of 14 Syrian soldiers were killed on Friday in battles with the Islamic State (IS) militants in the eastern province of Deir al-Zour, a war monitor reported.
The battles have been raging for days in the western countryside of Deir al-Zour, said the Syrian Observatory for Human Rights.
The Britain-based watchdog group said five IS militants were killed in the battles on Friday.
Earlier in the day, the observatory said the IS militants killed six members of the Syrian military intelligence in Deir al-Zour.
The IS ambushed the military personnel on the road between the city of Mayadeen and Deir al-Zour provincial capital, said the observatory.
A day earlier, the observatory reported intense battles between the Syrian army and the IS militants in the desert region in the western countryside of Deir al-Zour.
Tens of Syrian soldiers and IS militants have been killed in months of battles in the Syrian desert in eastern Syria.
After losing key areas across the country, the IS now has a presence in the Syrian desert region in the remote eastern countryside of Homs province and Deir al-Zour province.