Israeli military said it launched airstrikes at the Gaza Strip on Tuesday night after the Israeli flag march through Jerusalem al Quds.

Iran PressMiddle East: Israeli military claimed that the airstrikes carried out in response to incendiary balloons fired by the Palestinians in the besieged territory, putting fragile ceasefire in jeopardy.

The exchange marked the first major flare-up between Israel and Gaza since a May 21 ceasefire ended 12 days of devastating hostilities between the two.

In a statement, the Israeli military said that its warplanes had attacked compounds of the Palestinian Islamic Resistance Movement, Hamas early on Wednesday local time.

A Hamas spokesman, confirming the Israeli attacks, said it would continue to pursue its “brave resistance and defend the Palestinians’ rights and sacred sites” in Jerusalem al Quds.

At least 255 Palestinians were killed, including 66 children and 39 women, and more than 1,900 others injured in 12 days of Israeli airstrikes on the Gaza Strip. Israeli attacks in the West Bank also killed at least 34 Palestinians since April 13.

The Israeli onslaught came to a halt under an Egyptian-brokered truce, which took effect in the early hours of May 21.