The death toll from violence in Gaza has risen to 29, including six children, the health authorities in Gaza said Sunday, correcting a previous statement that had said 32 people were killed. 

Rocket sirens sounded and explosions were heard in Israeli communities west of Jerusalem on Sunday, Reuters cited witnesses as reporting.

That indicated possible rocket attacks and Israeli aerial interceptions on the third day of a flare-up in fighting around the Gaza Strip.

Twenty members of the PIJ were arrested overnight by Israeli security forces in the West Bank, the Israeli army announced on Sunday. 

The Israeli air force on Saturday night targeted a house in the southern Gaza Strip city of Rafah without warning, killing two Palestinians and wounding more than 30 others, Palestinian security sources told Xinhua.

Israeli army spokesperson Avichai Adraee said in a statement that the raid targeted Khaled Mansour, the commander of the southern brigade of PIJ.

The PIJ confirmed the death of Mansour on Sunday in a statement saying, "Al-Quds Brigades (Jerusalem Brigades) mourns the leader Khaled Mansour, member of the security council and the commander of the southern region (of Gaza Strip) who was martyred as a result of an Israeli air strike yesterday (Saturday)."

Meanwhile, at least five people, including four children, were killed and 15 others injured by an explosion in the refugee camp of Jabaliya in northern Gaza on Saturday night, according to Palestinian sources. Israel denied being responsible for the explosion, saying that a rocket misfired by the PIJ militants caused "the tragic killing of the children" in Jabaliya.

Egypt said it was engaged in intensive talks to calm the situation. Further escalation would largely depend on whether Hamas, the Islamist group which controls the Gaza Strip, would opt to join the fighting alongside the PIJ.

An Egyptian intelligence delegation headed by Major General Ahmed Abdelkhaliq arrived in Israel on Saturday and will be traveling to Gaza for mediation talks, two Egyptian security sources told Reuters. They were hoping to secure a day's ceasefire in order to carry out the talks, the sources added.

The cross-border clash, which shattered more than a year of relative calm around Gaza, began when Israel launched a surprise attack on Friday, killing a PIJ commander and hitting a series of what it said were military targets.

UN and European Union Mideast envoys expressed concern about the violence, and the Western-backed Palestinian Authority condemned Israel's attacks.

Tensions rose this week after Israeli forces arrested a PIJ commander in the West Bank, drawing threats of retaliation from the group. The military said it had apprehended 19 more group members on Saturday.

(With input from agencies)