Three mortar shells fired from Gaza hit southern Israel on Thursday, the army said, just over two hours after a humanitarian ceasefire took effect.

The shells struck in the region of Eshkol, which borders the southern Gaza Strip, the army told AFP, blaming Hamas but without giving further details.

There were no immediate reports of damage or casualties. Hamas did not immediately comment on the incident.

The mortar fire interrupted a ceasefire called for by the UN on humanitarian grounds, which both Israel and Hamas had agreed to observe between 0700 GMT and 1200 GMT.

Fighting since Israel launched Operation Protective Shield on July 8 to stamp out rocket fire by Gaza militants has killed 230 Palestinians, many of them women and children, and one Israeli.

Israel has carried out more than 1,750 attacks in Gaza, mostly air strikes, the army says, and fighters have fired nearly 1,400 rockets, 1,048 of which have hit the Jewish state.