JERUSALEM, June 3 (Xinhua) -- The Israeli air force launched an air strike on Gaza on Sunday night for the third time over the past day, amidst a new round of escalation between Israel and Gaza militants.

A military spokesperson confirmed in a statement that fighter jets struck 15 sites in Gaza, saying the attack was a response to the firing of rockets towards Israel earlier.

In the Israeli attack, the air force hit a rocket and weapons manufacturing and storage facility in the central Gaza Strip and other sites in the region of Khan Yunis in the southern Gaza Strip, the spokesperson said.

In addition, an urban warfare training facility was bombed in the neighborhood of Shuja'iyya, and infrastructure belonging to the Hamas naval forces was struck too.

Since Saturday night, rocket fire exchange from Gaza and Israeli air strikes were resumed after a few days of calm, threatening to break a de facto cease-fire that halted mutual fire last week.

Also on Sunday, Israel struggled to put out fire caused by kites with incendiary devices launched by Palestinians in the besieged enclave.

The escalation came after Israeli forces shot and killed at least 122 Palestinians since the demonstrations started a months ago, most of them killed during protests in the vicinity of the fence to protest the blockade imposed by Israel and the inauguration of the new U.S. embassy in Jerusalem.