Students in the southern city of Ashdod whose schools are unprotected from rockets will stay home Friday, in light of fears of continued rocket fire out of Gaza.

Officials in Ashdod made the decision late Thursday, hours after a rocket was fired for the second straight night, setting off sirens in the nearby Ashkelon region.

Security officials estimated that the rocket landed inside the Gaza Strip.

The school closure will affect some 3,500 kids in Ashdod, out of 54,000. Most of the unprotected schools in Ashdod sit in the ultra-Orthodox part of the city, according to Israel Radio.

In the seaside city of Ashkelon, schools will be held as normal, even in unprotected schools.

Late Wednesday night, a volley or eight rockets were shot toward Ashkelon. Five of them were downed by Iron Dome anti-missile batteries, and the other three fell in open areas outside of the city.

There were no injuries or damage.

“I really hope this isn’t the start of a new escalation, because it’s seemed the last few days that there has been an increase in fire,” Hof Ashkelon Regional Council head Yair Farjoun told Ynet after the attack. “The drizzle of the last few days can easily turn into something more violent.”

In response to the late-night barrage, the Israeli Air Force conducted airstrikes on four sites in northern Gaza, including a hidden rocket launcher, a weapons storage site and a weapons manufacturing facility. The IDF Spokesperson’s Unit reported direct hits on all targets.

Palestinian medical sources said a woman and four children were injured as a result of the strikes.

An Israeli security official said Thursday that Israel would respond forcefully to any attacks, though it did not believe Hamas, which controls the Strip, was behind the firings, Reuters reported.

Southern Israeli cities in proximity to Gaza were the targets of constant rocket fire for years before Operation Pillar of Defense in November 2012. Rocket fire from the Strip was reduced dramatically following the 8-day Israeli military campaign, though sporadic fire has persisted.