The Israeli military has bombed several targets in the Gaza Strip hours after the prime minister threatened to use a "disproportionate response" to fresh rocket fire from the Palestinian territory.
Palestinian witnesses reported huge explosions on Sunday and the Israeli military confirmed attacks on half a dozen locations, including an abandoned police station in northern Gaza and suspected smuggling tunnels in the south near the Egyptian border.
No casualties have been reported from the Israeli raids on Gaza, which come days before Israeli voters head to the polls to elect a new prime minister.
The military said Sunday's attacks were the beginning of a new wave of raids over Gaza, but did not elaborate, reports Al Jazeera's Hoda Abdel Hamid from Gaza City.
Ehud Olmert, Israel's out-going prime minister, said that the military would respond to attacks in a "severe and disproportionate" fashion after at least 10 rockets and mortar shells hit southern Israel on Sunday.
"We've said that if there is rocket fire against the south of the country, there will be a severe and disproportionate Israeli response to the fire on the citizens of Israel and its security forces," Olmert said on Sunday at a weekly cabinet meeting.
The Israeli military and rescue services said one of the Palestinian mortars that hit the village of Nahal Oz, next to the Gaza border fence, wounded two Israeli soldiers and a civilian.
The al-Aqsa Martyrs Brigades, the military wing of the Fatah faction led by Mahmoud Abbas, the Palestinian president, told Al Jazeera that it carried out the attacks.
The Hamas faction seized control of the Gaza Strip from Fatah forces in June 2007, but several other Palestinian groups, including the al-Aqsa Martyrs Brigades, continue to operate in Gaza.
Israel, however, holds Hamas responsible for all rocket fire coming from Gaza.
Israel and a Hamas-led group of Palestinian factions declared separate ceasefires last month after a 22-day Israeli offensive on the Gaza Strip that killed at least 1,300 Palestinians, many of them women and children.
Thirteen Israelis were also killed, three of them civilians, by Palestinian rockets and mortars.
Halting the Palestinian fire was one of Israel's stated aims for the air, naval and ground assault that also caused thousands of injuries and destroyed much of the territory's infrastructure.
But there has been sporadic rocket fire across the border and a number of Israeli air raids since the ceasefires were announced.
Olmert said at the cabinet meeting: "The situation ... in recent days has increased in a manner that does not allow Israel not to retaliate in order to make sure that our position ... is understood by those involved in the fire.
"The response will come at the time, the place and the manner that we choose."
Tzipi Livni, the foreign minister and one of the candidates to replace Olmert after parliamentary elections on February 10, also used the cabinet meeting to threaten further action against Hamas.
Livni, who heads Olmert's Kadima party, said that Israel must respond to rocket attacks "immediately".
|Sporadic rocket fire and Israeli air raids have continued despite the truce [GALLO/GETTY]
"We mustn't sign arrangements with Hamas, but rather use force against this organisation," she said.
"Israel will respond whether the Qassam [rocket] causes injuries or not, and this is how I will act as prime minister as well. We must use force and a lot of force."
Ehud Barak, the defence minister and rival candidate to Livni, said "Hamas was given a very serious blow and if necessary it will be given another blow".
Gideon Levy, a journalist and political analyst for the Israeli newspaper Haaretz, told Al Jazeera that the attack was directly linked to the elections.
"There is a domestic struggle between candidates and who will be more extreme and who will take a hardline stance towards the rocket fire coming from Gaza," he explained.
"The main lesson is that the Palestinians and Israelis did not learn any lessons from the war - it will bring more agony and destruction. Both parties are in a game of fools."
Ron Kampeas, an Israeli political analyst, said the underlying motive of the strikes was that the ruling Kadima party wanted "to show it is as hawkish as the Likud".
He told Al Jazeera that Benjamin Netanyahu, the leader of Likud, appeared likely to win the February 10 election and that Livni was now trying to keep her job as foreign minister in a coalition government.
Kampeas added that it remained to be seen whether Netanyahu, if he won, would form a coalition with Avigdor Lieberman, who is seen as further right than Netanyahu, which "could mean an even more hardline stance towards Hamas".
Taher al-Nunu, a Hamas spokesman, said in a statement on Sunday: "We condemn the statements by Olmert and others today threatening the Gaza Strip."
"This is an attempt to find a false excuse to escalate the aggression against the Palestinians, to destroy the Egyptian efforts to improve the calm and to use pressure against the Palestinian people to accept Israeli conditions in those talks."
Egyptian mediators have been attempting to secure a longer-term ceasefire addressing Israel's concerns over rocket attacks and weapons smuggling into Gaza, as well as Palestinian demands for the Israeli siege of the territory to be lifted.