Four Qassam rockets were fired from the Gaza Strip into Israel Thursday, causing no injuries.

One rocket was fired at Sderot Thursday evening prompting the Color Red alert to go off. The Qassam apparently exploded in an open area near the town.

Earlier in the evening, two rockets landed near the southern city of Ashkelon, while another rocket landed in the Ashkelon Beach region, near a kibbutz.

The two rockets near Ashkelon exploded around 9 pm in an open area south of the city. The anti-rocket alert was activated in facilities and factories in the city's southern industrial zone, prompting employees to take cover.

Ashkelon Mayor Benny Vaknin said that security officials asked him to "maintain full alert ahead of the possible firing of Qassams and Grad missiles" after the Gaza-bound flotilla left on its way to the Strip.

"To our great regret, we already experienced such fire," he said. "We very much hope not to see an escalation in the near future."

On Tuesday, the Air Force responded to Qassam attacks on the south by striking several targets across the Gaza Strip, killing three Islamic Jihad and Popular Resistance Committees members.