Iran's arsenal was badly depleted by Israeli attacks and retaliatory salvos during a 12-day war in June, but Iran may be seeking to replenish its stocks despite European-triggered UN sanctions which resumed last month and aim to bar arms transfers.
But sodium perchlorate appears to fall beyond the ban, even as Russian and Iran opposed the renewed curbs and argue against any fresh hostilities in the region.
Ten to twelve shipments of the material began arriving from China in Iran on September 29, the European intelligence sources cited by CNN said, and contain around 2,000 tons of the material which can be turned into solid propellant for mid-range conventional missiles.
Iran has rejected reported US demands that it curb the range of its missiles to achieve any peace deal, calling the requests a non-starter which curbs its defense.
Several of the vessels are already subject to US sanctions for earlier transfers, the sources added, but there was no indication of Chinese state involvement.
Beijing reaction
Reached for comment by CNN, China's foreign ministry said it was not familiar with the situation but that Beijing has “consistently implemented export controls on dual-use items in accordance with its international obligations and domestic laws and regulations.”
It further called for the lingering standoff between Iran and the West over Tehran's disputed nuclear program to be resolved through dialogue, calling the latest sanctions “unconstructive” and a “serious setback”.
Unofficial accounts pointed to sodium perchlorate and other compounds imported from China for Iran’s missile program as the cause of an April 26 blast at the Bandar Abbas port which killed 57 people. Authorities have denied any military link.