Israel launched two airstrikes on northern Gaza early Wednesday, after Palestinian militants launched a missile at nearby Netivot, despite a truce, dpa reported.
One man was injured when the Grad missile landed in the southern Israeli town, east of Gaza City, Tuesday night, a military spokeswoman in Tel Aviv told dpa.
She said the Israel Air Force struck two rocket launching sites in northern Gaza at about 2 am (0000 GMT) Wednesday. Palestinians reported that a bamboo workshop was destroyed and nearby shops damaged in one of the two strikes, on the outskirts of Gaza City.
Gaza militants fired seven other rockets and mortar shells over the border into Israel Tuesday, the military spokeswoman said, despite an Egyptian-brokered informal truce which took effect at 1 am.
No more projectiles landed in Israel Wednesday, she said.
Israeli Prime Minister Benjamin Netanyahu warned late Tuesday he would respond to each violation of the calm.
"Our message is clear: Quiet will bring quiet. Whoever violates it or even tries to violate it - we will find him," he told a meeting of government ministry officials in Jerusalem.
Thousands of Islamic Jihad supporters marched in Gaza City late Tuesday, marking a "victory" after the four days of violence, during which militants fired more than 200 rockets at southern Israel, and Israel launched some three dozen airstrikes.
Exiled Islamic Jihad leader Ramadan Shalah, addressing the crowd by phone, threatened that his faction was ready to launch missiles deeper into central Israel, the next time it attacked Gaza.
Some 25 Palestinians have been killed since the latest round of violence erupted Friday, after Israel assassinated the Popular Resistance Committee's (PRC) secretary-general Zohair al-Qaisi, who was allegedly planning a large-scale cross-border attack against Israelis. Four were civilians, including a 12-year-old boy killed by shrapnel while on his way to school. The rest were Islamic Jihad and PRC militants.