A drone strike killed four people in government-held eastern Syria on Wednesday in an area controlled by Iran-backed factions, a war monitor said.
"Four people were killed and eight wounded in a drone strike near a weapons factory belonging to Iran-backed groups and near a truck loaded with weapons," Rami Abdel Rahman of the Syrian Observatory for Human Rights told AFP.
There was no immediate word on who carried out the strike in the eastern city of Deir Ezzor.
It targeted a part of the city that is home to residences of top Iranian commanders and senior officers of Lebanon's Hezbollah movement as well as an Iranian hospital to treat cholera patients, Abdel Rahman said.
Pro-Iran factions aligned with the Syrian government, including Hezbollah, are heavily deployed south and west of the Euphrates River which runs through Deir Ezzor province.
State media said a landmine planted by "terrorists" exploded in the same neighbourhood, causing casualties.
"A number of citizens were killed and wounded when a landmine planted by terrorists exploded in the Al-Hamidiya neighbourhood of Deir Ezzor," state news agency SANA reported.
Wednesday's attack followed a series of unclaimed drone strikes on January 30 that targeted a suspected Iranian weapons convoy in the province and killed 11 people, including a pro-Iranian commander, the Observatory said at the time.
The conflict in Syria started in 2011 with the brutal repression of peaceful protests and escalated to pull in foreign powers and global jihadists.
The war has killed nearly half a million people and forced around half of the country's pre-war population from their homes.