A pair of cargo ships tied to a sanctioned Iranian state shipping line have quietly departed a Chinese chemical hub and are now sailing toward Iran carrying what analysts suspect is missile fuel precursor, according to fresh Washington Post analysis of ship-tracking data and satellite imagery.

The vessels have been identified as Shabdis and Barzin, which operate under Islamic Republic of Iran Shipping Lines (IRISL), the state carrier sanctioned by Washington and many allies. The IRISL has long been accused of shipping materials tied to Iran's ballistic missile program - something which the US and Israel say they are trying to currently eliminate in the ongoing Operation Epic Fury.

Both ships recently docked at Gaolan port in Zhuhai on China’s southeastern coast, a major chemical-handling facility that processes large volumes of industrial compounds, including sodium perchlorate - which is critical for producing solid rocket fuel, the report says.

Officials and and analysts were cited in the Post as concluding the cargo likely includes sodium perchlorate destined for Iran’s missile program.

"Given the track record, the most parsimonious explanation is that they're loading the same commodity they've been shuttling for the past year-plus," Isaac Kardon, a senior fellow at the Carnegie Endowment for International Peace, pointed out.

So in a way this is nothing "new" for Beijing-Tehran 'illicit' trade, however what is new is seen in the following:

While a dozen other IRISL ships have visited the port since the start of the year, experts emphasized that China's allowing a ship to depart for Iran with weapons-related material during a war in which they have called for restraint would be extremely notable.

Indeed, as Kardon continues, "China could have held these vessels at port, imposed an administrative delay, invented a customs hold – any number of bureaucratic tools, but didn't."

Just days before US and Israeli bombs began to fall on Tehran, we featured analysis which questioned, Will China Come To Iran's Rescue? "While China avoids direct confrontation, it has not shied away from visible military cooperation - also as "Earlier this month, Russia, China and Iran deployed naval vessels for joint security exercises in the strategically vital Strait of Hormuz," we featured.

Beijing's official position remains that it supports "safeguarding Iran’s sovereignty, security, and territorial integrity" while opposing "the threat or use of force in international relations." As was also featured:

China is unlikely to dispatch troops or engage directly in any conflict, but to interpret this as passivity would be to misread the nature of 21st-century great power competition. China's support for Iran is real, multifaceted, and in some ways more sustainable than military intervention; it just operates on a different strategic wavelength.

Beijing has meanwhile formally rejected the allegations that it is moving missile-production material to the Islamic Republic, arguing that the United States exaggerates routine commercial or dual-use trade.

And the below is a monitoring report from just weeks before the Trump-ordered campaign on Iran began:

Washington has directed parallel criticism at Russia and China's 'dual-use' trade and cooperation in certain sensitive industrial sectors which overlap with defense. But both also see this as their right, in the end, based on national sovereignty.