Gaza - Three Palestinians were killed Saturday when a tunnel used for smuggling beneath the Gaza-Egypt border collapsed, medics and witnesses said.

Witnesses said the three had been working on the tunnel, which collapsed near its end on the Egyptian side. The dead were taken to Egyptian hospitals in the northern Sinai city of al-Arish.

Palestinian medics said the deaths brought the number of Palestinians killed in such tunnels to 50.

Smuggling tunnels have increased as Israel and Egypt maintain the 16-month-old closure of commercial and travelers' crossing points into the Gaza Strip.

Rafah Mayor Eissa al-Nashar estimated there were 400 tunnels used to bring food, livestock, household items and fuel into the besieged Hamas-run Gaza Strip, with his Hamas-controlled municipality regulating the movements inside the lifeline tunnels.

Egypt has intensified its action against the tunnels since it brokered a ceasefire between Hamas and Israel in June 2008.

Under the deal, Israel has to ease the blockade in exchange for a halt in Palestinian attacks against Israeli communities near Gaza.

Hamas argues that Israel has not allowed a free flow of goods into Gaza, despite the calmer situation.

Over the past couple of days, heavy blasts have been heard on the Egyptian side of the border which tunnel operators say resulted from ends of tunnels being blown up by Egyptian forces. (dpa)