CAIRO, Nov. 13 (Xinhua) -- The Arab League (AL) on Tuesday denounced the escalation in the Gaza Strip which caused the death of six Palestinians.

In press statements, AL Assistant Secretary General for Palestine and Occupied Arab Lands Affairs Saeed Abu Ali held Israel responsible for the consequences of the "aggression."

He called on the international community to immediately intervene to "stop the Israeli aggression and to provide international protection for the Palestinian people."

According to Palestinian Health Ministry, death toll in the Israeli airstrikes on Gaza since Sunday has risen to 13, all militants, with 30 injured.

The abrupt flare-up was sparked by a failed Israeli undercover raid in Gaza on Sunday night.

The undercover soldiers, reportedly on a reconnaissance mission, were discovered by Hamas fighters, prompting a fire exchange that cost the lives of seven Palestinian militants, including a Hamas commander and an Israeli military officer.

The sudden burst of violence potentially shattered hopes for a long-term agreement between Israel and Hamas, as Egyptian and the UN officials have been working to broker a cease-fire deal in exchange for easing the 12-year blockade on Gaza.