Two Palestinian teenagers were killed on Saturday in a barrage of Israeli air strikes on the Hamas-controlled Gaza Strip. The Palestinian movement retaliated by firing scores of rockets at Israel The flare-up came after Israeli troops shot and killed two Palestinians, including a teenager, and wounded hundreds of others in border clashes on Friday, the latest in months of protests. Israel has decided "to take strong action against Gaza aggression", an Israeli government official said on Saturday after the worst flare-up of fighting since a 2014 Israel-Gaza war. Three Israeli were wounded from a rocket that landed on a residential home. Lt. Col. Jonathan Conricus said the latest Israeli sortie, the third of the day, struck some 40 Hamas targets including tunnels, logistical centers and a Hamas battalion headquarters. He said the escalation was the result of the sustained Hamas rocket attacks, its fomenting of violence along the border and its campaign of launching incendiary kites and balloons that have devastated Israeli farmlands and nature reserves. "Our message to Hamas is that we can and will enhance the intensity of our effort if needed," he said. "What Hamas is doing is pushing them ever closer to the edge of the abyss ... Hamas will have to understand that there is a price to be paid." Among the main targets was the "Hamas Battalion HQ in Beit Lahia, which includes urban warfare training facilities, (a) weapon storage warehouse, training compounds, command centers, offices and more", the Israeli army said in a statement. "A weapons manufacturing site and storage facilities housing various types of weapons, including Hamas naval capabilities" were also hit, the statement added. Later, witnesses reported that Israeli warplanes dropped four bombs on an unfinished building near a Hamas police and security compound in Gaza City, reducing the old structure to rubble. The four-story building is adjacent to a public park. Gazas Health ministry said two teenagers were killed in the strike and ten others injured. Hamas spokesman Fawzi Barhoum said the group was responsible for Saturdays barrage against Israel and that it was carried out "in response to the Israeli air strikes". "The protection and the defense of our people is a national duty and a strategic choice," Barhoum said. Palestinians in Gaza have for months been demonstrating against Israels decade-long blockade of the territory and in support of their right to return to lands they fled or were driven from during the war surrounding the creation of Israel in 1948. In fresh violence Friday, a 15-year-old was shot dead during the demonstrations and a 20-year-old died later of gunshot wounds sustained during the protest, the Gaza health ministry said. Since the protests and clashes broke out along the border on March 30, at least 141 Palestinians have been killed by Israeli fire. No Israelis have been killed, but officials said one soldier was injured by a grenade on Friday.