Four rockets fired from northern Gaza on Thursday evening landed in Israeli territory, but caused no injuries or damage.
It is not yet clear whether the artillery fired was composed of Qassam or Grad-type rockets.
One rocket, which was fired at around 5:30 pm, apparently landed on the outskirts of Ashkelon, but its exact landing site has yet to be located. A second rocket, fired two hours later, landed in an open area within the Sdot Negev Regional Council limits.
Two more rockets were fired towards Sderot and the Shaar HaNegev Regional Council at around 9 pm. The rockets have not yet been found, but no injuries or damage were reported.
Meanwhile, Gaza City was dark Thursday night after officials shut down its only power plant as Israel cut off fuel and food shipments to the Palestinian territory because of renewed rocket attacks.
Israel canceled plans to ship in diesel fuel for the plant as well as 30 trucks full of humanitarian supplies after Gaza militants fired at least eight rockets and some mortar shells at Israel Thursday, the military said.
Kamal Obeid, a Hamas official at of the power plant, said its closure cut off electricity to much of Gaza City's 300,000 residents.
'Rockets natural response to Israeli aggression'
Israel said the plant provides less than a quarter of Gaza's electricity, and most of the rest flows in unimpeded on power lines from Israel.
Renewed tensions in Gaza have raised the grim prospect of an end to a truce that has stopped most Israeli-Palestinian violence in and around the impoverished seaside territory for five months.
The truce began eroding last week when Israeli forces entered Gaza to try destroy what they said was a militants' tunnel. Eleven militants have been killed since and more than 130 rockets and mortars have been fired from Gaza at Israel. Israel has clamped a tight blockade on Gaza, which is ruled by the Islamic militant group Hamas.
"The rockets are a natural response to (Israel's) aggression," said Fawzi Barhoum of Hamas.
Government spokesman Mark Regev said Israel wants quiet.
"The current round of violence is the sole responsibility of Hamas, who through their aggressive acts have endangered the lives of too many Israeli and Palestinian civilians," he said.
The truce ended months of rocket barrages that disrupted life in southern Israel and brought Israeli airstrikes and ground operations in response. It is set to expire next month.
Both sides have said they are interested in maintaining calm, but developments on the ground appear to be going in the other direction.
Associated Press contributed to the report