GAZA CITY (AFP) - Israeli warplanes carried out three air strikes in the Gaza Strip over the weekend, without causing casualties, the army and Palestinian witnesses said on Sunday.

They said two of the raids targeted the south of the Palestinian territory while the other hit Gaza City.

"Our planes on Friday night attacked a structure in Gaza City being used to build weapons and carried out a twin raid on Saturday night on tunnels in the south of the territory" on the border with Egypt, an army spokesman said.

The air strikes came after Palestinian militants in Gaza fired a rocket and a mortar shell against southern Israel, the spokesman said, also without causing casualties.