Romanian navy continuously patrolling on the Lower Danube according to a CIA report dated 7 September 1950

An item reported that every Eastern Bloc ship sailing on the Lower Danube river between Braila and Sulina was escorted by a Romanian patrol vessel armed with 10-12 rocket launchers while this part of the river was strictly guarded. On the river banks were barbed wire barriers by the Soviets made and wood built towers on a concrete foundation fitted out with telephones made (long) distance communication possible.

Source
The report was published on www.archive.org, document number voorrangCIA-RDP82-00457R005700260006-2