Israeli planes bombed four targets in the Gaza Strip overnight, killing three Palestinians, including a 15-year-old boy, hospital officials said Friday, DPA reported.
The Israeli military said the targets hit were two smuggling tunnels in the southern town of Rafah, on the border with Egypt, a blacksmith shop in Gaza City used for "manufacturing weapons," and another tunnel in central Gaza.
The military said that tunnel was dug one kilometre from a security fence on the central Gaza border, by Palestinian militants seeking to infiltrate Israel for an alleged attack.
The four airstrikes came after militants in Gaza fired a barrage of mortar shells at Israeli farms late Thursday, as well as a rocket that hit south of the Israeli coastal city of Ashkelon. It was the first time a rocket hit near the Mediterranean city in months.
Officials at Abu Yousif An-Najjar hospital in Rafah said one Palestinian was killed immediately in the airstrikes on the smuggling tunnels at around midnight, but two more bodies were found under the rubble Friday morning.
At least to other people were injured.
The Popular Resistance Committees (PRC) militant group said in a leaflet that its fighters had launched the volley of mortar shells toward the Kerem Shalom crossing in south-eastern Gaza earlier Thursday.
The volley was revenge for the killing of two PRC fighters in an Israeli airstrike in Gaza Tuesday, which in turn was retaliation for earlier rocket and mortar fire.
Since Israel's three-week offensive in Gaza last winter, both it and the radical Islamist Hamas movement running the strip have largely abided by an unofficial truce.
Hamas has on a few occasions detained a number of militants who launched missiles and rockets into Israel.
Some 280 rockets and mortars have been fired at Israel since the end of last winter's war, compared to more than 3,300 in the year building up to it, according to the Israeli military.
Israel has responded to the ongoing sporadic fire by launching what it says are pinpointed airstrikes, mostly on the smuggling tunnels along the border with Egypt.
But violence between Israel and Palestinian militants in the Gaza Strip has lately increased.
The Israeli military vowed in a statement sent to journalists that it would continue to respond to any attempt by militants "to disrupt the calm in Israel's southern communities."