GAZA, Oct. 2 (Xinhua) -- Islamic Hamas movement is upset about Egypt's mounting security campaign on the borderline area between Egypt and the Gaza Strip, a well-informed source in Gaza said Tuesday.

The source, close to Hamas and speaking on condition of anonymity, told Xinhua that the movement watches with anger and disappointment the latest developments along the border.

Dozens of smuggling tunnels underneath the borderline of Egypt and Gaza were sealed off or destroyed, the source said, adding that the Gaza Strip's interests would be harmed if Egypt finds no alternative to the tunnels, through which fuels and foods are brought to the enclave after Israel imposed a tight blockade on the Gaza Strip in June 2007.

Egypt intensified its security campaign on the tunnels after the deadly attack carried out by radical Islamists on Aug. 5 during which 16 Egyptian soldiers were killed and seven others were wounded.

According to other well-informed sources in Hamas, Egypt has either destroyed or shut down 350 out of 800 tunnels operating underneath its borders with the Gaza Strip.

Following the Aug. 5 attack, Hamas has expressed its readiness to close all the tunnels, only if Egypt creates an alternative and open a joint free trade area between Egypt and the Gaza Strip.

The Palestinian National Authority (PNA) also accepted the idea of closing all the smuggling tunnels, but opposed to open a free trade area controlled only by Hamas, which seized control of the enclave in 2007.

Hundreds of Hamas supporters have demonstrated for several days, calling on Egyptian President Mohamed Morsi to help the Palestinians finding an alternative to the tunnels.