Israel's armed forces announced that dozens of warplanes are targeting Hamas sites in the Gaza Strip, The Times of Israel reports.
Eyewitnesses say that explosions are echoing in Gaza, reports Reuters.
Previously, the Israeli Defense Minister announced that the militant group Hamas had started a war against Israel and promised that "Israel will win."
After a security cabinet meeting at Israel's military headquarters in Tel Aviv, Defense Minister Yoav Galant warned that Hamas "made a serious mistake" in launching rockets into southern and central Israel in its surprise early morning attack.
Mohammed Deif, a senior Hamas military commander, announced the start of the operation in a broadcast on Hamas media, calling on all Palestinians to fight, Reuters reports.
"This is the day of the greatest struggle and the last day of the occupation," Deif said.
He added that 5.000 rockets were launched.
"There will be no truce until the (Israeli) aggression and siege cease." We will not accept any transitional solutions," said the Hamas commander.
Israel announced that it had launched Operation Iron Swords in response to the Hamas attack.
The army spokesman announced that more than 2.200 rockets have been fired at Israel since this morning, and that Israeli forces are fighting Hamas members in at least seven locations.
At least five people were killed and at least 100 were injured in rocket attacks on the central and southern parts of Israel, according to Israeli media.
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