Rocket alert sirens rang out across southern Israel for a second straight night Thursday, as over a dozen rockets were fired from Gaza and a several-hour old ceasefire with Islamic Jihad threatened to unravel.

One missile, heading for a populated area of Netivot, was shot down by an Iron Dome anti-rocket battery, the IDF said.

The rest of the missiles hit open areas in the Sderot, Shaar Hanegev and Sdot Hanegev areas. No injuries or damage were reported.

Earlier in the evening, two rockets were launched at the Ashkelon region, sending residents scurrying for shelter. Both landed in open areas.

IDF spokesman Lt. Col. Peter Lerner said 17 rockets were fired at Israel all day on Thursday, including seven that hit open areas, one that was shot down, and eight that failed to clear the Strip.

However, media reports on the number of rockets varied, with some tallying 16 since the ceasefire began in the early afternoon.

The IDF said Thursday night it was deploying Iron Dome batteries to Beersheba and Ashdod, indicating it may be expecting hostilities to widen. Both cities are on the outer edge of the range of most Gazan rockets and are generally targeted during larger escalations in violence.

Gazan terror group Islamic Jihad denied it launched the attacks earlier in the evening and it wasn’t immediately unclear who fired the rockets. Cease-fire declarations have not always been honored by terror groups and the barrage raised doubts about the ceasefire offer.

Islamic Jihad had claimed responsibility for a barrage of over 60 rockets that hit Israel on Wednesday evening. Israel responded to those attacks by hitting 29 sites in Gaza from the air Wednesday night.

Thursday morning saw more sporadic rocket fire, drawing a response by Israeli planes, after which Islamic Jihad announced a ceasefire, ostensibly brokered by Egypt.

After the ceasefire announcement, Israeli officials said the military would respond to “calm with calm,” according to Israel Radio.

Three Gazans were also injured Thursday evening after attempting to launch a rocket from the northern strip. The rocket likely malfunctioned and exploded on the ground, sources in Gaza said.

Palestinian Authority President Mahmoud Abbas earlier condemned the escalating violence, including rocket fire from Gaza. ”We condemn all military escalation, including rockets,” he said at a press conference in Bethlehem with British Prime Minister David Cameron.

His statements came hours after Prime Minister Benjamin Netanyahu criticized Abbas for initially condemning Israeli airstrikes on the Strip, but not the rocket fire from Gaza that prompted them.

Thursday morning saw five rockets fired at southern Israel from the Strip. Two failed to reach Israel, while three set off warning sirens in Ashdod and Ashkelon.

The Iron Dome anti-missile system downed one of those rockets over Ashkelon, while two others fell in unpopulated areas.

Times of Israel Staff and AP contributed to this report