The deadly Hamas militant attack on Israel and the massive retaliation it provoked from Jerusalem have thrust President Joe Biden into a Middle East crisis that risks expanding into a broader conflict and has left him fending off criticism from GOP presidential rivals that his administration’s policies led to this moment.

The potential for prolonged and expanding violence could test Biden’s leadership on both the world stage and at home as he tries to navigate between demonstrating unflinching support for Israel and fostering a broader peace in the combustible Mideast, where sympathetic militants were quick to loudly praise the action by Hamas. Hundreds have been killed on both sides.

Lebanon’s Hezbollah group welcomed the attack as a response to “Israeli crimes.” The Iran-backed group, which holds similar goals as Hamas for the destruction of the Israeli state, fired rockets and shells on Sunday at three Israeli positions, drawing a response from Israel’s military with armed drones. A senior adviser to Iran’s supreme leader lauded the operation by Hamas, which said it was ready for a potentially long fight.

Several 2024 Republican presidential contenders immediately tried to pin a portion of the blame on Biden. They sought to tie his recent decision to release $6 billion in blocked Iranian funds in exchange for freeing five Americans who had been detained in Iran to Saturday’s complex attack by air, land and sea. The White House pushed back fiercely against the GOP criticism, noting that the money unfrozen last month in the prisoner swap has yet to be spent by Iran and can only be used for humanitarian needs.