Three Palestinians were killed on Monday as Israel struck the Gaza Strip in retaliation to a barrage of rocket fire over the weekend. The Israeli army said it had so far struck 70 militant sites in response to over 200 rockets fired by the Hamas movement that controls the coastal enclave. The flare-up came after a deadly Israeli special forces operation in the Gaza Strip on Sunday that left Hamas vowing revenge. Missile defenses had intercepted 60 of the rockets and most others fell in open areas, though some hit houses and other civilian structures, the military said. Medics reported at least seven Israelis wounded. The army said an Israeli bus was hit by an anti-tank missile from the Gaza Strip in the area of the Kfar Aza kibbutz, causing several injuries. A soldier was severely wounded, it said. A joint statement from Palestinian armed groups in Gaza, including Hamas, claimed responsibility for the rocket fire and the missile attack on the bus, which it said was being used by Israeli soldiers. Israeli military spokesman Jonathan Conricus said he could not yet provide further details on the bus or its passengers. Gazas health ministry said three Palestinians were killed in the Israeli strikes and nine wounded. The Popular Front for the Liberation of Palestine said two were its members, while the third was from Jihads armed wing. Hamas said the rocket fire was in revenge for the deadly Israeli operation late Sunday. On Sunday, a clash erupted during the covert operation in the Gaza Strip that killed seven Palestinian gunmen, including a local commander for Hamass armed wing, as well as an Israeli army officer. Prime Minister Benjamin Netanyahu cut short a trip to Paris and rushed home as tensions rose, and on Monday convened a meeting of security chiefs. Israel had stressed its covert operation on Sunday was an intelligence-gathering mission and "not an assassination or abduction", but Hamas strongly denounced it and vowed revenge. Israel signaled that Sundays mission did not go as planned and resulted in the clash, which Palestinian officials said included Israeli air strikes. The clashes came after months of deadly unrest along the Gaza-Israel border had appeared to be calming. Recent weeks have seen Israel allow Qatar to provide the Gaza Strip with millions of dollars in aid for salaries as well as fuel to help ease an electricity crisis. Before the flare-up, Netanyahu had defended his decision to allow Qatar to transfer the cash to Gaza despite criticism from within his own government over the move, saying he wanted to avoid a war if it was not necessary. Israel and Palestinian groups in Gaza have fought three wars since 2008, and recent months have raised fears of a fourth. Deadly clashes have accompanied major protests along the Gaza-Israel border that began on March 30. At least 231 Palestinians have since been killed by Israeli fire, the majority shot during protests and clashes, while others died in tank fire or air strikes. Two Israeli soldiers have been killed in that time. Egyptian and UN officials have been mediating between Israel and Hamas in an effort to reach a long-term truce deal.