Up to 55 rockets as well as mortar rounds were fired from the Gaza Strip Wednesday at southern Israeli towns.

No Israeli casualties were initially reported in the largest attack from the Strip since Operation Pillar of Defense in late 2012.

Most of the rockets were reported to have fallen in open areas, though at least one rocket landed in a residential neighborhood. Damage was reported in two impact sites.

Four consecutive alarms were heard by residents of Sderot as well as the nearby Eshkol Regional Council. Residents throughout the entire region were instructed to remain in protected areas. Explosions were heard in Sderot, Netivot and surrounding areas.

Some of the rockets were reported to have been launched from the east Gaza City neighborhood of Shuja’iyya.

IAF jets were reportedly flying over the Strip, apparently in an effort to thwart further rocket launches.

The army said three of the rockets were intercepted by the Iron Dome defense system.

Officers in the southern command were set to convene Wednesday evening to discuss possible responses to the attack.

Meanwhile, security agencies in the Strip evacuated their headquarters for fear of Israeli reprisal, Sky News reported.

An alarm was also heard in Beersheba, although it was unclear whether a rocket was actually fired at the major city, which is further away from the Strip than the smaller towns of Sderot and Netivot.

“I heard some explosions,” Ya’akov Shoshani, a resident of Netivot, told Channel 2. “I exited the taxi I was in and clung to the wall for safety.”

Rafi, a resident of Sderot, told the news channel that a rocket had nearly hit his home. “A Kassam [rocket] fell next to my house, right on the sidewalk. Luckily there were no casualties.”

The Islamic Jihad took responsibility for firing some of the rockets at Israel, and indicated that the attack was retaliation for the Tuesday killing at the hands of the IDF of three Islamic Jihad operatives as they prepared to fire at Israel from the Gaza Strip.

“The Al-Quds Brigades responded to (Israeli) aggression with a volley of rockets,” the group said in a statement Wednesday, minutes after the rocket attack.

Following the rocket attack, Prime Minister Benjamin Netanyahu said Israel would forcefully respond to any threat on its citizens.

“It seems that the rocket fire came in response to our counter-terrorism operations yesterday,” Netanyahu said. “We will continue to thwart and harm those who wish to harm us, and we will act against them with great intensity.

“Last year, the number of rockets fired from Gaza was the lowest in a decade, but we will not settle for that. We will continue to ensure the security of Israeli citizens in the south and throughout the country.”

Last week, Israel intercepted what it said was an Iranian shipment of rockets intended for terror groups in Gaza. Israeli military sources said the arms, including 409 rockets, were destined for Islamic Jihad.

AFP contributed to this report.