Italian Prime Minister Mario Draghi tendered his resignation Thursday after his coalition collapsed because of differences over how to respond to the fallout of the war in Ukraine, leaving the eurozone’s third-largest economy in political crisis.

Mr. Draghi said he would resign after a key party in his coalition pulled its support for his government following squabbles among the groups on whether to send arms to Ukraine and how much financial support to give to Italian families reeling from high inflation.