Egypt has begun building a concrete wall along its border with Gaza, said AFP journalists and a Palestinian security official from Islamist movement Hamas, which controls the enclave, on Wednesday.

Dozens of workers aided by cranes could be seen erecting the structure, which will stretch from Gaza's southeastern tip to the Rafah crossing with Egypt, the only gateway out of Gaza that does not lead into Israel. 

The wall is being built along the lines of an old, lower barrier that includes an underground structure designed to curb smuggling tunnels between Gaza and Egypt.

Contacted by AFP, Egypt's military declined to comment on the new structure. 

A Hamas security source told AFP that the goal was "to complete (the wall) as quickly as possible." 

"The important thing for us is to control the border and prevent any illegal activity there", including any cross-border trafficking, the source said.  

A security delegation from Egypt led by General Ahmed Abdel Khalek, who heads Palestinian affairs at Egypt's intelligence agency, was in Gaza last week seeking to restore calm between Hamas and Israel. 

Hamas and the Jewish state have fought three wars since 2008.

Egypt, long a mediator between the two sides, and key Gaza donor Qatar strongly pushed for de-escalation last year.  

A truce was quietly agreed but it was not endorsed by Islamic Jihad, another major armed group in Gaza that Israel says is backed by Iran. 

Israel's military said Wednesday that it had "identified a sniper squad of the Islamic Jihad terror organisation" firing on troops from Khan Yunis in Gaza. 

It said no troops were injured but Israeli forces returned fire and "a hit was identified."

Officials in Gaza said an Islamic Jihad fighter was slightly injured.