“The building went up in flames,” police spokesman Micky Rosenfeld said, adding that rescue crews were on scene and the fire appeared to be under control. Magen David Adom said it had treated four people for light injuries.Late Saturday night, the IDF struck three rocket- launchers in Gaza, the army said.Another rocket fired in the salvo landed in the Nativ Ha’asarah area north of the Strip but caused no damage or injuries. The Code Red rocket siren was sounded in two communities in southern Israel ahead of the attack. Alerts also went off in the Hof Asheklon Regional Council and the Sha’ar Henegev Regional Council.At around 10 p.m. on Saturday, Palestinian terrorists in Gaza fired two more rockets at southern Israel. The projectiles triggered warning sirens, and exploded in open areas in the Sdot Negev region, failing to cause injuries or damages.(Video: Tazpit News Agency)The rocket attacks followed an air force strike in northern Gaza on Friday in which two Popular Resistance Committee members were killed.Usama Hasumi and Muhammad Fatiah had in recent weeks taken part in the firing of rockets at Israeli communities, the IDF said. In recent days, they planned to carry out “severe terrorist attacks against residents of the State of Israel,” the military said.Hours later, four Gazan rockets exploded in open areas in the Eshkol region, failing to cause injuries or damage. A fifth hit in the Hof Ashkelon region. Later, an Iron Dome anti-rocket battery intercepted two Gazan projectiles over the Ashkelon region.The Israel Air Force struck four targets in the Gaza Strip early on Saturday in response to the rocket fire from the Hamas-run enclave the previous evening. Targets included a weapons manufacturing site in central Gaza and a weapons depot in southern Gaza, the military said.“The IDF will continue to act with determination, as much is needed against any element that carries out terrorism against Israel. The Hamas terrorist organization, and all of its branches, is the address, and it is responsible,” the army added.Defense Minister Moshe Ya’alon said southern communities had suffered rocket fired launched by the two terrorists killed in the air strike. “We don’t intend to ignore any [rocket] fire on Israel, or any attempt to harm our civilians and IDF soldiers. We will pursue and strike with a mighty hand anyone who does this or plans to, as we’ve done today. We see Hamas as responsible for what happens in Gaza, and it should not test our patience or determination.”Ya’alon said Israel will continue to act “responsibly and with good judgment to allow residents who live near Gaza, and the southern communities, and Israeli civilians in general, to continue with routine life.”The air strikes on terrorist targets, and Palestinian rocket fire on civilian communities in Israel, came days after the air force bombed seven targets in the Gaza Strip in response to three rocket attacks against southern Israel.The Iron Dome anti-rocket battery intercepted two rockets south of Ashkelon last week, and a third struck an open area in southern Israel. The air force hit targets in Gaza that included five underground rocket launchers and two terrorist facilities that were used as weapons depots.A number of the targets in Gaza belonged to Hamas, a senior security source said.The European Union on Saturday said, “We condemn recent indiscriminate rocket fire from Gaza. We call on all sides to exercise maximum restraint and to avoid any further escalation which will worsen the situation.”Tovah Lazaroff and Jerusalem Post staff contributed to this report.