Israeli warplanes launched twin air strikes on the Gaza Strip overnight in a response – deemed disproportional by Arab commentators – to rocket fire from the Palestinian resistance in Gaza, an army spokesman said on Monday.
The strikes targeted so called "centres of terrorist activities, which have been hit", said the spokesman, referring to projectiles fired from Gaza over the weekend.
Israel considers the Islamist Hamas movement as the only organisation responsible for the firing of the missiles "even if it does not claim responsibility," said the spokesman.
In December 2008, Israel launched its calamitous "Operation Cast Lead" into the Gaza Strip claiming self-defence.
The 22-day war, which ended in a ceasefire on 18 January 2009, killed 1,400 Palestinians, mostly civilians and 13 Israelis, 10 of them soldiers.
In its wake the number of Palestinian attacks dropped significantly, although 230 rockets and mortar rounds were fired at Israel during 2010, according to army figures.
Right wingers in the Israeli government called on Sunday for tough military action against Gaza's resistance fighters after border clashes killed and wounded several Palestinians.
"The government must consider afresh a policy of zero tolerance, exert a heavy price, not let this situation deteriorate," National Infrastructure Minister Uzi Landau told journalists at the weekly cabinet meeting.
"It needs to stop," added Landau, a veteran hawk from Prime Minister Benjamin Netanyahu's Likud party.
The military said two rockets had slammed into southern Israel on Sunday, one shortly after midnight and a second later in the morning, bringing the number of rockets and mortar rounds fired across the border this year to 20.
On Saturday, three people on an Israeli kibbutz were wounded, two of them seriously, by mortar fire from the Gaza Strip, for which the militant group Islamic Jihad claimed responsibility.
That followed a border firefight between Palestinian combatants and Israelis on Friday in which an Israeli soldier was killed by the same mortar he intended to fire.
Israel has so far responded to nearly every instance of projectile fire with air strikes on the Gaza Strip.