Israel says it is prepared to respond with great force after a long-range Grad missile fired from the Gaza Strip landed in the southern Israeli port city of Ashkelon.
Israeli officials say no one was injured when the rocket struck in the middle of a street in a residential area.
Over 1,000 killed in three-week offensive
It was the first long-range rocket to be fired from Gaza since Israel and rival Hamas leaders declared separate cease-fires more than two weeks ago, ending a 22-day Israeli assault on Gaza. Palestinian officials and human rights groups say the offensive killed nearly 1,300 people.
Israel responded immediately with threats of a new assault if the rocket attacks continue.
Prime Minister Ehud Olmert's spokesman, Mark Regev, told VOA Israel blames Hamas for any new, large-scale violence that erupts.
"Hamas is acting to deliberately undermine any possibility of quiet," Regev said, "deliberately undermine any possibility of sustained peace and quiet for the people in the South. And, if escalation is about to happen, Hamas has no one but themselves to blame."
Hamas willing to stop attacks in exchange for guarantees
The attack came as Egypt continues efforts to mediate a sustained truce between Israel and Hamas. A Hamas official, Mushir Al-Musri, told Israel Radio his group is prepared to stop its attacks if it gets the guarantees it seeks.
He said that if Israel commits to a cease-fire and opens the border crossings, Hamas will be committed "in iron" to halting attacks. The Hamas official said there would be no more rockets or other attacks.
Hamas has offered a one-year cease-fire if Israel lifts its blockade on all border crossings.
Israel imposed the blockade after Hamas seized control of Gaza following elections in 2006. The militant Islamist group does not recognize Israel and its charter calls for the destruction of the Jewish State.
Analysts say continuing violence bolsters Netanyahu campaign
The rocket attack on Ashkelon is the latest of several incidents of violence since the January 18 cease-fire. A roadside bomb on the Gaza border killed one Israeli soldier last week and Israel has carried out a number of air strikes on militant targets. Residents of southern Gaza said Israeli aircraft bombed smuggling tunnels Tuesday on the border with Egypt.
Political analysts say the continuation of violence appears to be bolstering the campaign of hard-line candidate for Prime Minister Benjamin Netanyahu before national elections take place next Tuesday. Polls show Mr. Netanyahu in the lead, ahead of Foreign Minister Tzipi Livni and Defense Minister Ehud Barak.
Netanyahu visited the scene of the rocket attack in Ashkelon and Israeli news reports quoted him as saying "the only way to remove the rocket threat is to topple the Hamas regime."