I'm planning to travel to Eastern Syria to Deir ez Zur. Is it safe to go near the Iraqi border?
I would like to visit Duros Europos and Mari and would like to know the current condition in that area.
There is no problem in visiting that area as a tourist.It could be better if you hire a tour guide as you get close to borders .

If you do not have a hired car and guide. It is the same mini-bus for Mari and Dura Europos, the fare should cost £50SP to Dura Europos, from the down town mini bus station in Deir ez-Zur, as opposed to the bus station on the outskirts of town. (Check in with the Police officer at the minibus station before you find your minibus). You'll need water and a snack for the time you are in the ruins. The site at Dura Europos is exposed to the weather.
On the Syrians' side of the border, at the sites, it's very tranquilo, on the bluff of Dura Europos with the Euphrates below. To return to Deir ez-Zur by public transport should not be a problem. You will only be near the Iraqi border, if you are exiting Syria, and tooled up with a visa, and truckin' on into Iraq.