As part of the 2026 Iran war, the unfinished B1 bridge in Karaj, Iran, was attacked on 2 April 2026 by the United States with two missiles, causing it to partially collapse. Eight people were killed and at least 95 were wounded. According to Iran's Fars News Agency, the second strike occurred once first responders had arrived to assist victims of the first strike. The deputy governor of Alborz province said the victims were civilians celebrating Sizdah Be-dar in the area below the bridge. The attack came amid United States president Donald Trump's threats to destroy Iranian civilian infrastructure.