A Palestinian was killed and three others were wounded Sunday afternoon in an Israeli airstrike in central Gaza Strip, medical sources and witnesses said.

The airstrike puts the number of Palestinians killed in this round of violence to four. Israel started a series of aerial raids in Gaza since Saturday evening.

The latest airstrike targeted a group of militants riding a three-wheeler tuk tuk to the east of Deir al-Balah city in the middle of Gaza Strip.

A medical spokesperson said one of the three wounded was in a critical condition.

Security sources said the militants were likely members of a radical Salafi groups affiliated with the Global Jihad organization. Israel blames the organization for attacking its territories from the Hamas-controlled Gaza Strip and the neighboring Sinai Peninsula.

In the morning, Israel killed a Palestinian militant hours after it killed two others. The militants were hit while riding motorcycles in northern and southern Gaza Strip.

Israel said the raids target militants gearing to fire a rocket into its territories.

One of the dead in the first airstrike was identified as Hisham al-Saidani, the leader of the Tawheed and Jihad, a radical Islamic group affiliated with the Global Jihad organization.

Al-Saidani was released from a Hamas-run prison in August. He was held as part of Hamas' efforts to curb the Salafist groups from consolidating their base inGaza.

Israel said that al-Saidani's group was responsible for firing a Grad rocket into Western Negev Friday. The rocket fell in the yard of a house and caused slight damage.