The Israeli air force and Gaza militants traded sporadic fire on Wednesday night but a fragile truce between the sides that ended four days of violence appeared to be largely holding.
Late Wednesday night aircraft struck at farmland near Gaza City and an uninhabited area near the southern town of Khan Yunis, causing no injuries in either case, Palestinian security officials said.
The Israeli military said that the raids were in reponse to the firing from the Gaza Strip several hours earlier of a rocket aimed at the southern Israeli city of Beersheva, which was brought down by the Iron Dome missile defence system, also with no casualties.
"Aircraft targeted a rocket launching site in the northern Gaza Strip and a terror tunnel in the southern Gaza Strip," a military statement said.
Earlier on Wednesday, militants fired a projectile but it struck Palestinian territory, police said.
State-run Channel One television said that in light of Wednesday's fire, schools in Beersheva and the other southern cities of Ashkelon and Ashdod would again close on Thursday as a safety precaution, after reopening on Wednesday following a three-day closure.
On Tuesday, in the hours after the truce was announced, police said eight rockets and mortar rounds were fired into Israel.
In the early hours of Wednesday, Israeli warplanes carried out two strikes that were said to be a response to the rocket fire, targeting "two terror activity sites in the northern Gaza Strip."
Palestinian security sources confirmed one strike, saying it set ablaze a wood yard without causing any casualties.
Israeli Prime Minister Benjamin Netanyahu went before parliament on Wednesday evening and tied the conflict in Gaza to tensions with Iran over its nuclear programme, which Israel says masks a weapons drive.
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He accused the Israeli opposition, which supported the withdrawal of settlers and troops from Gaza in 2005, of having given Iran the chance to take over the territory.
"They put Iran into Gaza and we will take it out," he said.
"What's happening in Gaza is Iran. Where do the missiles come from? Iran. Where does the money come from? Iran. Who trains the terrorists? Iran. Who builds the infrastructure? Iran. And often who gives the orders? Iran.
"Gaza is an advance post for Iran," he said.
"I hope that the whole world today understands that the terrorist organisations in Gaza -- Hamas and Islamic Jihad -- and also Hezbollah in Lebanon, are sheltered by the Iranian umbrella.
"Can you imagine what would happen if that umbrella was nuclear?"
Netanyahu warned on Tuesday that the truce, agreed after four days of violence, would be short-lived if rocket fire resumed.
"Calm will bring calm. Anyone who disturbs it, or even tries to disturb it, will be in our gun sights," he said.
The truce, mediated by Egypt, ended violence that began on Friday with Israel's assassination of a senior Palestinian militant. Militants responded by firing hundreds of rockets into the Jewish state.
Under the terms of the truce, both Israel and militants from Islamic Jihad, who were responsible for most of the rocket attacks, have agreed to hold their fire.