President Barack Obama on Thursday told Israeli Prime Minister Benjamin Netanyahu that Washington was ready to mediate to achieve a cease-fire between Israel and Hamas, and he appealed to both parties to "restore calm" to overcome a conflict that has caused 88 deaths in the past 72 hours, the White House said.

In a telephone conversation, Obama told Netanyahu that the United States "remains prepared to facilitate a cessation of hostilities, including a return to the November 2012 cease-fire agreement" brokered by then-Secretary of State Hillary Clinton.

Obama reiterated Washington's "strong condemnation" of the firing of rockets against Israel by Hamas and other terrorist organizations and reaffirmed "Israel's right to defend itself against these attacks," the White House said in a statement.

"The President expressed concern about the risk of further escalation and emphasized the need for all sides to do everything they can to protect the lives of civilians and restore calm," the statement added.

In another telephone conversation, Palestine National Authority chief Mahmoud Abbas asked Secretary of State John Kerry to intervene to secure an immediate cease-fire.

Israel's military offensive against Gaza over the past 72 hours has resulted in 88 deaths, most of them civilians.

The latest crisis between Israel and the Palestinians erupted on June 12, when Israel began a massive search for three Jewish seminary students who went missing in the West Bank and were found murdered last week.

Israel blamed the kidnappings on Hamas, which has denied any role, and arrested 500 people, most of them linked to the group.

Tensions between the two sides flared after a Palestinian teenager was abducted in Jerusalem last week and found burned to death hours later in a revenge killing for the murders of the three Israeli students.

Israeli security forces have arrested six people in connection with the murder, one of whom has confessed and confirmed the involvement of the other accused. EFE