WASHINGTON>> They are smooth white boxes, about the size of large cargo vans, and they are at the heart of the U.S.-Chinese technology conflict.

As the United States tries to slow China’s progress toward technological advances that could help its military, the complex lithography machines that print intricate circuitry on computer chips have become a key choke point.

The machines are central to China’s efforts to develop its own chipmaking industry, but China does not have the technology to make them, at least in their most advanced forms. This week, U.S. officials took steps to curb China’s progress toward that goal by barring companies globally from sending additional types of chipmaking machines to China, unless they obtain a special license from the U.S. government.

The move could be a significant blow to China’s chip manufacturing ambitions. It is also an unusual flexing of American regulatory power. U.S. officials took the position that they could regulate equipment manufactured outside the United States if it contains even just one American-made part.

That decision gives U.S. officials new sway over companies in the Netherlands and Japan, where some of the most advanced chip machinery is made. In particular, U.S. rules now will stop shipments of some machines that use deep ultraviolet, or DUV, technology made mainly by the Dutch firm ASML, which dominates the lithography market.

Vera Kranenburg, a China researcher at the Clingendael Institute, a Dutch think tank, said that although ASML had made clear that it would follow the regulations, the company was chafing under earlier regulations that barred it from exporting a more sophisticated lithography machine to China.

“They’re, of course, not happy about the export controls,” she said.

After being thrust into geopolitics yet again, ASML has been careful in its response, saying this week it complies with all laws and regulations in the countries where it operates. CEO Peter Wennink said the company would not be able to ship certain tools to “just a handful” of Chinese chip factories. But “it is still sales that we had in 2023 that we’ll not have in 2024,” he added.

In a statement, the Dutch foreign trade minister, Liesje Schreinemacher, said the Netherlands shared U.S. security concerns and continuously exchanges information with the United States, but that “ultimately, every country decides for itself what export restrictions to impose.” She pointed to more permissive restrictions announced by the Dutch government in June.

A spokesperson for the U.S. Department of Commerce declined to comment.

ASML’s technology has enabled leaps in global computing power.

The increasing precision of its machines — which have tens of thousands of components and cost as much as hundreds of millions of dollars each — has allowed circuitry on chips to get progressively smaller, letting companies pack more computing power into a tiny piece of silicon.

The technology also has given the United States and its allies an important source of leverage over China, as governments compete to turn technological gains into military advantages. Although Beijing is pouring money into the semiconductor industry, Chinese chipmaking equipment remains many years behind the prowess of ASML and other key machine suppliers, including Applied Materials and Lam Research in the United States and Tokyo Electron and Canon in Japan.

But U.S. efforts to weaponize this technological advantage against China appear to be straining alliances. In Europe, government officials increasingly agree with the United States that China poses a geopolitical and economic threat. But they are still wary of undercutting their own companies by blocking them from China, one of the world’s largest and most vibrant tech markets.

Dutch technology, in particular, has been the focus of a multiyear pressure campaign from the United States. In 2019, the Trump administration persuaded the Dutch to block shipments to China of ASML’s most state-of-the-art machine, which uses extreme ultraviolet technology.

After months of diplomatic pressure from the Biden administration, the governments of the Netherlands and Japan agreed in January that they also would curb sales independently of some deep ultraviolet lithography machines and other types of advanced chipmaking equipment to China.

The United States and its allies have viewed sales of the deep ultraviolet lithography machines as less of a national security risk. The chips they produce are considerably less advanced.

But that position was tested this summer when a Chinese firm used ASML’s deep ultraviolet lithography technology along with other advanced machines to blow past a technological barrier that U.S. officials had hoped to keep China from reaching.

In August, Chinese telecom giant Huawei unexpectedly released a new smartphone containing a Chinese-made chip with transistor dimensions rated at 7 nanometers, just a couple of technology generations behind the latest chips made in Taiwan.

Analysts have concluded that China’s Semiconductor Manufacturing International Corp. made the chip with the use of the Dutch deep ultraviolet lithography machinery.