JERUSALEM/GAZA (Reuters) - Gaza militants fired rockets at Israel on Saturday drawing retaliatory Israeli air strikes on Hamas sites, the Israeli military said, a few days after the area’s most intense fighting in years.

At least four projectiles were fired from Gaza at Israel, the military said in a statement, adding that three were intercepted and one fell short.

Rocket alerts sounded in Israeli towns and villages near the border after dark, sending residents rushing to shelters. None of Gaza’s militant groups claimed responsibility for the rocket fire.

Residents in Gaza said Israeli aircraft struck at least three sites belonging to Hamas, the Islamist group which controls the enclave.

The Israeli military confirmed in a statement it had carried out the air strikes, adding that “the Hamas terror organization is solely responsible for all events that transpire in the Gaza Strip and emanate from it.”

There were no immediate reports of casualties in any of the incidents.

Israel and Palestinian armed groups in Gaza reached a de facto ceasefire this week after the most intense flare-up of hostilities since a 2014 war, both sides signaling they did not want a wider escalation.

Militants from Hamas and Islamic Jihad fired dozens of rockets and mortar bombs at southern Israel throughout Tuesday and overnight into Wednesday, to which Israel responded with tank fire and air strikes on more than 50 targets in the small, coastal enclave.

Violence along the Israel-Gaza frontier has surged in recent weeks. At least 120 Palestinians have been killed by Israeli troops during mass demonstrations along the Gaza border that began on March 30.

Israel, which has drawn international condemnation for its use of deadly force, says many of those killed were Hamas members and militants trying to launch attacks under cover of the protests.

The Palestinians say most of the dead and the thousands wounded were unarmed civilians against whom Israel was using excessive force.

More than two million Palestinians are packed into the narrow coastal enclave. Israel withdrew its troops and settlers from Gaza in 2005, but maintains tight control of its land and sea borders, citing security concerns.

Egypt also restricts movement in and out of Gaza on its border.