Israel has opened a new phase in its war on Hamas by expanding ground operations inside Gaza, but analysts warn the campaign is its riskiest in half a century with fallout threatening the whole Middle East.

Thousands of civilians have already died in Gaza and Israel since Hamas launched its shock Oct. 7 attacks. And the United Nations has led warnings that thousands more will die as Israel sends troops and tanks farther into Gaza.

That adds to Western fears that Iran-backed Hezbollah could open a new front on the Lebanese border. Officials say Israel does not want to stay in Gaza and there are also concerns over who will administer the territory and pay for its reconstruction after the guns fall silent.