On two separate occasions last year, railroad cars carrying tens of thousands of kilograms of smokeless powder — enough propellant to collectively make at least 80 million rounds of ammunition — rumbled across the China-Russia border at the remote town of Zabaykalsk.

The powder had been shipped by Poly Technologies, a state-owned Chinese company on which the US had previously imposed sanctions for its global sales of missile technology and providing support to Iran. Its destination was Barnaul Cartridge Plant, an ammunition factory in central Russia with a history of supplying the Russian government.

These previously unreported shipments, which were identified by Import Genius, a US-based trade data aggregator, raise new questions about the role China has played in supporting Russia as it fights to capture Ukrainian territory. US officials have expressed concerns that China could funnel products to Russia — what is known as “lethal aid” — though they have not said outright that China has made such shipments.

Speaking from Beijing on Monday, Antony J. Blinken, the US secretary of state, said China had assured the US that it was not providing lethal assistance to Russia for use in Ukraine and that the US government had “not seen anything right now to contradict that”. “But what we are concerned about is private companies in China that may be providing assistance,” Blinken said.

Some experts said the shipments Poly Technologies had made to Barnaul Cartridge Plant since the invasion, which totalled nearly $2 million, according to customs records, constituted such lethal assistance. According to the customs records, Poly Technology intended its shipments to be used in the kinds of ammunition fired by Kalashnikovs.

William George, the director of research at Import Genius, said that Poly Technologies “may be toeing the line on what constitutes lethal aid to Russia”, but that the implications of the shipments were clear. “When shipping large quantities of gunpowder intended for the creation of military cartridges to a country at war, it’s unreasonable to imagine that the finished product won’t be used to lethal effect,” George said.

New York Times News Service