Israeli security personnel examine the damage caused by a rocket from Gaza in Ashkelon, southern Israel, Oct. 29, 2011. Israel and Palestinian militant groups in the Gaza Strip launched rounds of retaliatory attacks against each other on Saturday, leaving seven Palestinians killed and several from both sides wounded. [Xinhua]

An unoccupied house in Ashkelon sustained damage from a direct hit, and fire department officials said they were trying to keep some nearby propane gas tanks from a fire breaking out as a result of the hit, Israel's Channel Two television reported Saturday night.

Israeli Home Front Command had instructed residents of cities and towns in a 40-kilometer radius around Gaza to remain in protected areas and not to assemble in groups of more than 500 people.

Adele Roemer, a resident of Kibbutz Nirim near Gaza, reported hearing blasts from beyond the border. "We were warned to stay within 15 seconds distance of protected areas," she told Xinhua.

A battery of the Israeli army's Iron Dome anti-missile system succeeded in downing one projectile fired towards Beersheba, according to the army.

Several militant groups in Gaza, including Al-Quds Brigades, have claimed responsibility for Saturday's rocket attacks on Israel.

Al-Quds Brigades said on Saturday evening that it had launched several long-range Grad rockets at central Israeli towns of Ashdod and Yavneh, as well as the southern Israeli town of Beersheba, as a response to the earlier killing of five of its militants.

"(The response) had started with hitting the (Israeli) cities of Ashdod and Yavneh and their suburbs with Grad rockets," the group said in a message sent via mobile phones to reporters in Gaza.

Earlier Saturday, the group issued a statement following the attack on its training base, saying that their response to the Israeli killing "will be hard."

The armed wings of two left-wing Palestinian groups, the Democratic Front (DFLP) and the Popular Front (PFLP), said in two separate statements that they also fired two Grad rockets and some mortar shells at southern Israel.

Al-Aqsa Martyrs Brigades, the armed wing of Fatah movement, also said in a leaflet that its militants fired a Grad rocket from the Gaza Strip at southern Israel in revenge for the killing of five Jihad militants.

The Israel Police announced that they were raising a national alert level to "G", one stage below the most severe alert, in response to the spike in attacks. Israeli Defense Forces Chief of Staff Lt.-Gen. Benny Gantz has convened senior staff to decide on further military responses to the continuing rocket fire.

Meanwhile, the Palestinian National Authority (PNA) called on the Palestinian militant groups in the Gaza Strip to be self- restraint and "not to give Israel an excuse to wage a war on the Gaza Strip."

The last escalation of violence between Israel and Gaza militant groups was in late August, when around 30 Palestinians and two Israelis were killed. A truce mediated by Egypt was then reached between the two sides.