RAMALLAH, May 5 (Xinhua) -- A senior Palestinian official on Sunday slammed Israeli attacks on "defenseless civilians," saying it is "a cynical attempt to inflict pain on Palestinians for political gains."

"Israel has turned Gaza into the largest open-air prison in the world ... (through) indiscriminately bombarding heavily-populated areas," Hanan Ashrawi, a member of the Palestine Liberation Organization (PLO) Executive Committee, said in an e-mailed statement.

She urged the international community to "end the escalation and to protect the rights and lives of 2 million Palestinians."

Meanwhile, Ahmad Majdalani, another member of PLO Executive Committee, confirmed that Palestinian President Mahmoud Abbas is holding talks on regional and international levels to "stop the ongoing Israeli offensive on Gaza Strip."

In addition, the Palestinian Foreign Ministry accused Israeli Prime Minister Netanyahu of "continuing his hideous assault against the Gaza Strip."

In a press statement, the ministry urged the International Criminal Court to promptly launch investigation into "Israeli crimes" in Gaza.

Earlier in the day, UN Special Coordinator for the Middle East Peace Process Nickolay Mladenov called for an immediate cease-fire in Gaza.

All parties should "immediately de-escalate and return to the understandings of the past few months," he said in a press statement.

At least 12 Palestinians have been killed and nearly 50 others wounded during Israeli airstrikes on the Gaza Strip since Saturday evening.