The US struck the Aq Tekeh-Khan railway bridge in Iran's northern Golestan province with cruise missiles, hitting a link on the rail corridor connecting Iran to China and Russia, state media reported on July 9.

The strike marks one of the deepest US attacks inside Iranian territory since the conflict began, extending the target list beyond military sites in the south to trade infrastructure that Tehran has leaned on to circumvent sanctions and sustain overland links with Beijing and Moscow.

The bridge, in the Aqqala district, sits on the China-Kazakhstan-Turkmenistan-Incheh Borun corridor, which enters Iran from the northeast and connects Gorgan to Tehran, according to the report. The route forms part of China's Belt and Road Initiative, running from Xian in China to Tehran.

At least 65 trains had travelled from China to Iran over the past year, and the number of transiting trains had tripled after the start of US pressure on Iran's ports, Fars said, citing foreign media.

Russia began shipping goods to Iran via the same rail route from late October, according to the report, which said analysts viewed the strike as going beyond a conventional military target. The claims could not be independently verified by IntelliNews.

The attack came at a time when US strikes since the ceasefire had focused on military targets in southern Iran near the Strait of Hormuz. Targeting a bridge near the Turkmenistan border represented one of the deepest US strikes into Iranian territory since the conflict began.

Iranian rail infrastructure has been struck before, with rail points, roads and bridges hit and rebuilt at speed, according to the report. In strikes on April 7, the US and Israel targeted six railway bridges in Tehran, Alborz, Qom, Isfahan, Zanjan and East Azerbaijan.

The Yahyaabad bridge in Kashan reopened three days later on April 10, while a bridge near Qom was repaired in under 40 hours.

The strike followed the collapse of a ceasefire agreed last month, after which the US revoked a licence allowing sales of Iranian oil and US Central Command said it had struck more than 90 Iranian targets.

Iran's Islamic Revolution Guards Corps said it had retaliated against US bases in Kuwait and Bahrain, while President Donald Trump declared the ceasefire over.