AMSTERDAM (Reuters) - Russian firms were able to obtain spare parts for 25-year-old ASML chipmaking machines in 2022 to 2023 on secondary markets despite European Union sanctions, Dutch newspaper Trouw reported on Thursday, citing Russian customs documents.

ASML, Europe's largest technology firm, dominates the market for advanced lithography systems, which use light beams to help create the circuitry of chips.

Although its 1990s-era tools are not considered "dual use" equipment with potential military applications, they would still be useful for Russian companies making analogue chips for the country's war in Ukraine, including for drones.

However, following Russia's 2022 invasion of Ukraine, European sanctions have blocked sales of electronics equipment to Russia.

ASML told Reuters that it abides by the sanctions, and that even before they were imposed, it had sold few tools in Russia.

"ASML doesn't sell products or services to Russia and doesn't interact with Russian distributors. Nothing has been sent by ASML to Russia in recent years and sanctions restrict the sale of PAS and Twinscan systems, as well as spare parts, to Russia" it said in an emailed response to queries.

The Trouw story focused on ASML's PAS-5500 tools, which date from the 1990s and 2000s, when ASML was an up-and-coming challenger to the top companies of the day, Japan's Nikon ( NINOF ) and Canon. It said Russian trading firms bought the spare parts through Chinese middlemen.

Reuters was not able to independently verify the report.

The PAS-5500 is no longer being built, but most of those made in the past are still in operation. Used machines are sometimes sold or refurbished and ASML makes and sells spare parts to accredited owners.

The Trouw story said it had viewed documents showing 170 instances of relevant spare parts being imported by Russian firms. It said the firms involved declined comment while the Chinese vendors were untraceable.

(Reporting by Toby Sterling; Editing by Emelia Sithole-Matarise)