The Netherlands has made public its plans to restrict the export of key chipmaking tools, a crucial step in the US’s ongoing effort to limit China’s access to high performance semiconductors, the Financial Times reports. The deal — which is expected to include controls on critical chipmaking tech from the Dutch multinational ASML Holding — was reached with the US in January but was made public this week when Dutch trade minister Liesje Schreinemacher wrote to parliament to outline the new measures.

ASML is a key player in the global chip supply chain, producing the tools that the likes of TSMC need to produce advanced semiconductors. Without its equipment, any domestic chipmaker in China will face significant challenges producing advanced chips. That’s a key US concern as it attempts to limit China’s ability to develop advanced military technologies like hypersonic missiles. The US announced wide-ranging chip sale restrictions of its own last October.

“Because the Netherlands considers it necessary on national security grounds to get this technology into oversight with the greatest of speed, the Cabinet will introduce a national control list,” Schreinemacher’s letter said, according to Reuters. New legislation to enact the new controls is expected to be introduced before the summer.

Reuters notes that the letter did not name China directly or explicitly mention ASML, the world leader in advanced chipmaking equipment that’s required to produce modern high performance chips. But the letter did call out deep ultraviolet (DUV) lithography systems, which ASML is currently able to sell to customers in China. After restrictions are introduced, companies are expected to need licenses to export this technology.

ASML reportedly doesn’t expect the restrictions to affect its previously announced financial forecasts. It expects sales to China to remain flat this year, even as overall sales increase by 25 percent. As well as DUV tools, ASML also produces more advanced extreme ultraviolet (EUV) lithography tools, although according to the Financial Times, it’s been banned from selling these tools to China since 2019. Reuters notes that it’s unclear whether ASML will be able to service machines previously sold to China.

As well as the Netherlands, the US is also understood to have made a deal with Japan for it to introduce similar export restrictions. Japan is yet to announce anything publicly, but Reuters notes that an update could arrive this week.

A spokesperson for the Chinese foreign ministry said the country opposed the plans. “We are firmly opposed to the Netherlands’ usage of administrative means to intervene and limit normal economic and trade exchanges between Chinese and Dutch companies,” Mao Ning said during a media briefing in comments reported by Reuters.