Israeli ground forces invaded southern Lebanon overnight Monday, marking a significant escalation in the nearly year-long war in the Middle East.New video released from the Israeli military reportedly shows soldiers preparing for what they are calling "targeted operations" in Lebanon. The raids are aimed at Iranian-backed terrorist group Hezbollah, following months of airstrikes between both sides.Hezbollah began firing rockets into northern Israel at the start of the war in Gaza in solidarity with Hamas. The strikes on both sides have escalated recently. An operation Israel is believed to be behind blew up Hezbollah communications devices. Further strikes from Israel knocked out most of Hezbollah's leadership.The fighting has killed over 1,000 people in Lebanon over the past two weeks, adding to the 41,000 Palestinians killed in Gaza and over 1,200 Israelis killed at the onset of the war.There is no word from Israel how long the targeted raids will last.In a conversation with Israel's defense minister, U.S. Defense Secretary Lloyd Austin affirmed U.S. support for Israel's right to defend itself.The White House has warned of wider regional war but characterizing this latest development as "within Israel's right to defend itself," adding that a diplomatic solution is the only way of achieving stability between Israel and Lebanon.Austin agreed with Israel's defense minister on dismantling Hezbollah's "attack infrastructure" along the Israel-Lebanon border. Austin says doing so could pave the way to allowing innocent people to return to their homes.The U.S. also says it is prepared to defend troops and other allies in the event the war escalates further through attacks from Iran or other Iranian-backed terrorist groups.The last time Israel and Hezbollah engaged in ground fighting was during a month-long war in 2006. Israel previously occupied parts of Lebanon for decades.