Israel’s security cabinet officially declared war Saturday night after Hamas terrorists launched a surprise barrage of thousands of rockets into southern Israel, killing hundreds and wounding thousands, according to Israeli media.Israeli soldiers battled Hamas fighters in the streets of southern Israel a day after Iranian-backed Hamas terrorists invaded the area and launched rockets from the Gaza Strip, killing at least 600 Israelis and wounding at least 2,000 others.Israeli forces launched retaliatory strikes against Hamas terrorists in Gaza on Sunday, while also trading fire with Lebanon’s Iran-backed Hezbollah militant group in the north.Israel struck 426 targets in Gaza, blasting residential buildings to the ground, including a 14-story tower that held dozens of apartments as well as Hamas offices in central Gaza City. Israeli forces fired a warning just before the strike.LIVE UPDATES: 300 DEAD, ISRAELI PM NETANYAHU DECLARES ‘WAR’ AFTER HAMAS TERRORISTS LAUNCH MASSIVE ATTACK An Israeli airstrike struck Gaza City on Saturday after Hamas militants carried out an unprecedented attack on Israel, firing thousands of rockets as dozens of Hamas fighters infiltrated the heavily fortified border in several locations by air, land, and sea. (AP Photo/Fatima Shbair) (AP Photo/Fatima Shbair)Among the 313 killed in Gaza were 20 children, and close to 2,000 wounded, the Palestinian Health Ministry said.Meanwhile, Israel’s northern border came under attack Sunday as Hezbollah fired dozens of rockets and shells at three Israeli positions in a disputed area along the border. Israel’s military returned fire using armed drones.During Saturday’s incursion, Hamas fighters reportedly captured women, children and the elderly. Israeli military officials confirmed that a “substantial” number of Israelis were abducted Saturday without giving an exact figure.An Egyptian official told the Associated Press, “It’s clear that they have a big number — several dozens” of hostages. The official said Palestinian leaders claimed that they don’t yet have a “full picture” of hostages, and those who were brought into Gaza were taken to “secure locations” across the territory.Hamas terrorists claim to have taken enough Israeli hostages to free all the thousands of Palestinian prisoners being held in Israel on Sunday.On Saturday night, Israel’s security cabinet voted to officially go to war, unlocking “significant military activities,” Prime Minister Benjamin Netanyahu’s office announced, according to the Times of Israel. It is Israel’s first declaration of war since the Yom Kippur War in 1973.Netanyahu had earlier declared war following the surprise attack on Israel, vowing that Hamas “will pay an unprecedented price.” He warned, “This war will take time. It will be difficult.”SCOTT SAYS US MUST STAND ‘SHOULDER-TO-SHOULDER’ WITH ISRAEL AFTER HAMAS TERROR ATTACK: ‘NEVER BACK DOWN’Deputy head of the Hamas political bureau, Saleh al-Arouri, told Al-Jazeera TV that it had planned for a long fight. “We are prepared for all options, including all-out war,” al-Arouri, said. “We are ready to do whatever is necessary for the dignity and freedom of our people.”CLICK TO GET THE FOX NEWS APPThe Biden administration “unequivocally” condemned terrorist organization Hamas on Saturday amid its unprecedented and “appalling” assaults against Israel. President Biden and senior administration officials stressed that the United States “stands with Israel.”The Associated Press contributed to this report.