The IDF late Sunday night launched a wide series of air strikes against Hamas targets in an apparent turning up of the heat for a rocket launched from the Gaza Strip Sunday afternoon, which had exploded in the southern Israeli community of Sderot between two homes near the local train station.Earlier Sunday, the IDF took a limited counterstrike, hitting only two Hamas targets in the northern Gaza Strip - one with air power and one additional terror infrastructure site by tank fire. At that earlier point, the army said only that it will "continue to act with determination at all times to guard the security of the citizens of the State of Israel," and it seemed that was the end of the altercation.The IDF would not identify its early Sunday targets other than that they were connected to Hamas. However, Palestinian reports indicated that the Israeli airstrike hit a Hamas lookout point and that an Israeli tank shell damaged a Beit Hanoun water tower.There were contrary reports about whether Gazans were injured in the IDF’s counterstrikes and how many were injured.Despite targeting Hamas, the IDF also refused to identify who was responsible for firing the rockets, but Palestinian reports initially indicated that it was the Abu Alu Mustafa Brigades, the military arm of the Popular Front for the Liberation of Palestine.Hamas responded to the strikes Monday morning, saying that "Israel is responsible for this escalation in the Gaza Strip." On Saturday, Jamil Mazhar, a member of the PFLP Politburo may have hinted the reason for the rocket attack relates to the ongoing administrative detention and 67-day hunger-strike of PFLP terrorist Bilal Kayed. Mazhar said that the coming days will be decisive, saying the PFLP will not for a moment turn its back on its comrade Bilal Kayed and calling on the occupation not to test the PFLP’s patience. “Those who support a cease-fire should take our message seriously because the occupation will not enjoy peace and security while the comrade Bilal Kayed is fighting death for the sake of freedom,” he added.At the same time, a source who spoke to The Jerusalem Post said that the Abu Ali Mustafa Brigades were denying responsibility for the attack.Late Sunday night, reports indicated that Ahfad a-Sahva, a Salafist group, had taken responsibility for the earlier rocket attack. The second much wider IDF counterstrike Sunday night also included a message to Hamas that it is the ruler of Gaza and must enforce the quiet even if it did not fire the rockets itself.Earlier Sunday, Hamas military wing spokesman Abu Obeida warned Israel that, “the Kassam Brigades and the Palestinian resistance is ready to defend our people at any time and fighting a battle can be forced upon us at any time. We warn the enemy of any guile, deception, adventure, or stupidity.” However, as of Monday morning, Hamas had not yet responded.Police confirmed that the site of the Gaza projectile's remains had been located in the city. 'Red Alert' rocket sirens were activated prior to the projectile's strike as residents in the area reported hearing an explosion.There were no initial reports of injuries or damage. Local residents were prohibited from entering the area until police bomb disposal experts concluded investigations. But there was no special instruction for residents to stay in their homes as the day went on.Sderot Mayor Alon David said, “Terror will not conquer us and will not break the fortitude of our citizens. These have been the quietest two years that this entire area has known and it cannot be that an isolated incident will violate the quiet.“We will continue forward and tonight we will all enjoy the festival ‘Heart of Sderot’, the summer festival of Sderot and the nearby areas,” he said.Former defense minister and current Zionist Union MK Amir Peretz responded to the attack, saying, “ I have no intention of challenging the current defense minister and it cannot be that a military operation would be part of a political or personal agenda.”He warned that it was important to strike the right balance in responding with a show of military strength, but without being unintentionally dragged into a broader escalation.After days of heavy activity and pronouncements, current Defense Minister Avigdor Liberman made no comment about the days events.The city of Sderot boasts a population of 19,000 residents. According to the IDF, 14 rockets from Gaza have been fired into Israel so far in 2016.The last rocket strike from Gaza was also on Sderot in the beginning of July and the IDF launched counter airstrikes against Hamas in that case as well.In late May, Ajnad Bait al-Maqdis, a salafi terror organization operating in the Gaza Strip claimed responsibility for a rocket strike on southern Israel.In response to rocket fire launched towards Israel on May 25, the Israeli Air Force attacked two Hamas terror infrastructure targets in the Gaza Strip.Adam Rasgon, Jerusalem Post Staff and Reuters contributed to this report.