JERUSALEM, Israel -- Hamas and a Gaza-based global jihadist group have launched more than 120 missiles, rockets and mortars at southern Israel since Monday. On Thursday morning terrorists continued firing rockets, launching 17 of them before 10:00 a.m., one igniting a fire, despite agreeing to a cease-fire.

It's a pattern Hamas has repeated over and over again since taking control of the Gaza Strip in June 2007:  bombarding Israel with hundreds of rockets for several days and then "agreeing" to an Egyptian-mediated cease-fire.

Usually, terrorists continue firing rockets for a day or two after the announcement. This allows them to accuse Israel of breaking the cease-fire when the IDF targets the terror infrastructure in response to continuing rocket fire.

That's exactly what's taken place following Hamas' announcement Wednesday night.

Two Grad-type Katyusha rockets were fired at the coastal city of Ashkelon overnight, one intercepted by an Iron Dome battery. Iron Dome batteries were also set up in Beersheva, Netivot and Ashdod.

Ashkelon Mayor Benny Vaknin announced that city schools would remain closed due to the security situation.

"The parents' committee representatives told me their children barely slept last night because of the sirens, and some of them suffer from anxiety. After consulting with security officials I decided to keep the schools closed," Vaknin said.

The rocket bombardment, Hamas claimed, is in "response to Israel's continued crimes against our people in the Gaza Strip."

"In response to the Egyptian efforts to try and stop the aggression on our people, we at al-Qassam Brigades and all resistance factions declare our commitment to stop this round of confrontation, as long as Israel commits to stopping its crimes," read the statement by the Izz al-Din al-Qassam Brigades, the "military wing" of Hamas, AFP reported.

"Our current confrontation with the enemy was kept at a minimal exchange of fire and it is best the Israeli leaders understand that very well," the statement read.

The latest round of trouble began last weekend when terrorists -- possibly from the Gaza Strip -- launched two Grad rockets at Israel from the Egyptian Sinai.

Then on Monday, a small terror cell infiltrated Israel from the Sinai and attacked a construction crew, firing an RPG and detonating an explosive device that killed an Israeli crewmember from Haifa.