Trump commented on the attack on the B1 bridge in the city of Karaj, around 35 kilometers west of Tehran, in a post on Truth Social.
"Iran's largest bridge is collapsing and will never be used again - much more to follow," the president wrote, sharing a video showing smoke rising from the bridge.
He further wrote in capital letters that it is "time for Iran to make a deal before it is too late."
The newly inaugurated bridge is one of the highest in the Middle East. According to Iranian state television, the bridge was hit twice, with the second attack allegedly occurring after rescue workers arrived at the scene, reported AFP.
At least eight people were killed and 95 injured, according to Governor Ghodratollah Seif.
Threatens to respond
In response to the bridge attack, Iran's Revolutionary Guard is threatening, according to the state news agency Fars, to attack bridges across the Middle East in countries such as Jordan and Saudi Arabia, Haaretz reported.
According to Iran's Health Ministry, the more-than-100-year-old Pasteur Institute, which conducts advanced medical research, in Tehran was hit and partially razed in another attack.
On Thursday, air raid sirens also sounded again in Israel, where several waves of Iranian attacks took place after the US president's televised speech. Rocket debris fell on several locations in Israel, according to police.
In a drone attack on the Iraqi capital Baghdad, a maintenance base belonging to the US diplomatic mission at the international airport was hit.
The Israeli military said on social media that its air force had carried out more than 20 raids on Iranian missile facilities in the past 24 hours. In targeted attacks, Jamshid Eshaghi, head of the regime's military oil headquarters, and a commander of the Iranian missile forces were killed, according to separate statements.
Contradictory messages from Trump
In recent days, Donald Trump has delivered conflicting messages about the war. On the one hand, he claims that new, "less radicalized" leaders have taken over in Tehran, and that they have asked the US for a ceasefire. On the other hand, he has promised bombing and annihilation.
Iranian representatives continue to deny that a ceasefire has been requested.
