Israel closed all but one of its border crossings with the Gaza Strip this morning in response to a mortar attack 24 hours earlier.
The Jewish state said one mortar shell was fired from Gaza yesterday and landed in southern Israel, causing no casualties or damage.
"All crossings, except for the Erez terminal, will be closed today because of the mortar fired yesterday," said defence official Peter Lerner.
Israel has responded to previous rocket and mortar salvoes by closing border crossings into the Gaza Strip, where the Islamist Hamas movement seized control a year ago by routing Palestinian President Mahmoud Abbas's Fatah forces.
Earlier this year, the European Union and international agencies described Israel's closure of crossings into Gaza and the cutting off of fuel deliveries as well as food and other humanitarian aid - as collective punishment - banned by the Geneva Conventions.
Under a truce brokered by Egypt on June 19, militants in Gaza are required to halt rocket and mortar fire in return for Israel gradually lifting a blockade of the coastal territory.