Gaza, Sep 7 : Israeli fighter jets attacked posts and facilities of the Islamic Hamas Movement in the Gaza Strip, security sources said on Tuesday. The strikes late Monday night, which had targeted military posts belonging to Hamas' armed wing al-Qassam Brigades near the southern Gaza Strip city of Khan Younis, caused severe damage to training facilities, with no immediate report of injuries, the sources told Xinhua news agency. Huge explosions were heard in the area, and Hamas militants fired back at the attacking war jets, witnesses said. The airstrikes on Hamas facilities were a response to the earlier launching of incendiary balloons from the Gaza Strip towards Israel, said an Israeli army spokesman in a press statement. The Israeli fighter jets struck a factory that produces cement used for building underground tunnels and another factory that manufactures rockets and makeshift projectiles, the spokesman added. Hamas spokesman Hazem Qassem said that the airstrikes on the Gaza Strip "express the Israeli failure to confront the struggle of the Palestinian people, mainly after the escape of six Palestinian prisoners from an Israeli jail". "The conflict between the Palestinian people and Israel will never stop until our people grab their legitimate rights and their full freedom and live on the lands of Palestine," Qassem said in a statement. Israel has launched multiple airstrikes on the Gaza Strip since the end of the last round of tension between Israel and Hamas-led militants that lasted 11 days and ended on May 21, leaving more than 250 Palestinians and 13 Israelis dead. /IANS