Two Palestinians suffocated inside a tunnel used by smugglers under the border between the Hamas-ruled Gaza Strip and Egypt on Sunday, local medics said.

Several Palestinians have died in similar incidents in recent months in the tunnels, which are used to smuggle arms, fuel and other supplies into Gaza. Just last Thursday two people died in the collapse of a smugglers' tunnel under the Gaza-Egypt border.

Dozens of tunnels run under the Gaza-Egypt border. Smugglers of fuel, weapons, drugs and other contraband have become increasingly daring since Israel and Egypt closed their borders with Gaza last year, following the violent Hamas takeover of the territory.

About a month ago Egyptian forces discovered 500 kilograms of explosives in the Sinai Peninsula. An Egyptian security source said at the time that the weapons were apparently supposed to reach Hamas forces in Gaza.

Also on Sunday, two mortar shells fired toward Israel from northern Gaza landed in Palestinian territory near Kibbutz Nahal Oz. No injuries or damage were reported.