Palestinians carry the body of militant into al-Najar hospital following an Israeli airstrike in Rafah on Oct, 29, 2011. Two Palestinian militants were killed and another two wounded on Saturday night in an Israeli airstrike on the southern Gaza Strip city of Rafah, while another five militants were killed earlier that day also in an Israeli airstrike, medics and witnesses said. (Xinhua/Khaled Omar)

GAZA/JERUSALEM, Oct. 29 (Xinhua) -- 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.

Five militants belonging to the Islamic Jihad (Holy War) movement`s armed wing Al-Quds Brigades were killed and another three were critically injured Saturday afternoon, when Israel launched an airstrike on a Jihad training post in the Rafah city in the southern Gaza Strip.

The killed included Ahmed al-Sheikh Khalil, a senior member who headed the group`s rocket engineering team.

Israel said the killed militants were behind two rocket attacks on central Israel two days ago.

Another two militants of Al-Quds Brigades were killed Saturday night in a second Israeli air raid on Rafah.

Eyewitnesses told Xinhua that the Israeli war jets fired a missile and struck a group of militants near the inoperative Gaza Airport in Rafah.

Two militants were also seriously wounded by the shrapnel of missile, according to medics at Abu Yousef al-Najjar.

The militants were trying to launch rockets at some targets in southern Israel, in revenge for the earlier Israeli airstrike on the training post, witnesses said.

After the first airstrike, Israeli Radio said around seven Russian-made long-range Grad missiles were fired from Gaza at several towns and cities in central and southern Israel, wounding at least five Israelis, including one resident of Ashkelon, two of Ashdod, and one man in Gan Yavne.

One of the injured was in critical condition, according to the radio.

The "barrage" of rockets had destroyed a school in Ashdod and several houses in central and southern Israel, the radio said.

"Ashdod is under attack, without doubt," said Yehiel Lasri, mayor of Ashdod.