Israel says Palestinian militants have fired at least five rockets toward southern Israel since an Egyptian-brokered cease-fire took effect on Tuesday.
Officials say no injuries have been reported from the rockets, which landed in open areas.
Earlier, Egypt said it had negotiated a truce between Israel and the Palestinian militants in the Gaza Strip, after four days of back-and-forth aerial attacks killed at least 25 Palestinians.
An Egyptian security official said the agreement includes an Israeli pledge to halt "assassinations." But a senior Israeli defense official, Amod Gilad, said that Israel will defend its citizens if necessary. "Quiet" from the Palestinian side, he said, will be met with "quiet" from the Israelis.
Israeli airstrikes in Gaza have wounded at least 80 people since Friday. Israel says most of those killed in Gaza have been militants.
The militants have fired more than 100 rockets at southern Israel, wounding several Thai agricultural workers, forcing schools to close and disrupting the lives of hundreds of thousands of Israelis.
The Palestinian militant group Islamic Jihad has claimed responsibility for most of the rocket fire.
The Quartet of Mideast peace mediators called for calm in the region, in a statement released Monday after a meeting of representatives in New York.
United Nations Secretary-General Ban Ki-moon also expressed grave concern about the latest escalation in violence between Gaza and Israel, saying civilians were paying a "terrible price." In remarks to the Security Council Monday, he said rocket fire on Israeli civilians is "unacceptable," and he also urged Israel to exercise "maximum restraint."
Some information for this report was provided by AP, AFP and Reuters.