Germany can forget about getting as much intelligence from US spooks as it currently does if it allows Chinese telecoms to build 5G infrastructure, a letter from the American Ambassador in Berlin has reportedly warned.

Washington is continuing to twist the arms of its European allies to discourage economic cooperation with its biggest geopolitical rival, China.

According to the Wall Street Journal, US Ambassador Richard A. Grenell sent a letter to the German Economy Minister, which said that Berlin should discriminate against Chinese companies like Huawei when selecting providers of 5G equipment to upgrade its networks.

Ignoring the warning may result in the US downgrading its intelligence-sharing cooperation with Germany, the letter dated last Friday said. American intelligence agencies like the NSA are an essential source of information for their German counterparts, which operate under stricter regulations in relation to spying, especially domestically.

Washington considers Chinese companies to be a potential threat, presuming that any equipment and software provided by them could potentially be used by Beijing to spy on other nations.

Huawei and ZTE already face restrictions on the American domestic market, while US officials are leaning on other nations to exclude China from the lucrative upgrade of wireless infrastructure to 5G standard.

Commenting on the report, Chinese Foreign Ministry Spokesperson Lu Kang said Washington should accept the fact that other countries may take strategic decisions independently, as is their right.

Beijing sees US attacks on Chinese telecom giants as baseless scaremongering and a not-so-subtle way of undermining a competitor through political leverage and legal attacks.

Berlin said that the US failed to provide any evidence that Chinese products would pose a security threat, adding it was willing to use them as long as they comply with Germany’s recently reviewed cybersecurity standards.

American officials say a backdoor may be sneaked through with a software upgrade and doubt the Germans would be able to detect it, considering the complexity and sheer volume of the code. “The Americans will assume that everything we share with Germany will end up with the Chinese,” a Senior US State Department official said, describing the American position to the WSJ.

The US, which is currently engaged in a trade war against China, is getting used to framing its opposition to Chinese economic expansion as a national security issue.

Just last week, the Italian government received a rebuke from a senior US security official for saying it would discuss with Beijing possible participation in China’s Belt and Road Initiative a major infrastructure project intended to improve links between the country and its major suppliers and markets.