Egypt says it has begun to install cameras and motion sensors along the border with Gaza to try to stop smuggling of weapons by Hamas through tunnels.
Tighter surveillance is one of Israel's key conditions for maintaining a ceasefire that ended a three-week offensive against Hamas on 18 January.
The tunnels were used to smuggle food and medicine, as well as arms.
Israel bombed them, but the BBC reports some were still usable when the fighting stopped and others have been repaired.
Egyptian security sources installation of the equipment has begun in along the 14km border with the help of American, French and German expertise.
Reuters news agency reports they hope the equipment will detect any new tunnel-building activity in the area. The United States has pledged $US32 million in equipment.
