Berlin should bar Huawei or other Chinese vendors from constructing Germany's 5G network or risk losing access to U.S. intelligence, according to a letter from U.S. Ambassador Richard Grenell to the country's economics minister, The Wall Street Journal reported Monday.

The two countries have been carefully rebuilding their intelligence sharing relationship since 2013 and 2014, when the U.S. and Germany were at odds over two spying scandals stemming from the revelations by Edward Snowden of NSA snooping. Last month, German officials said they "weren't ready" to ban Huawei equipment and were unsure of the legality of such a request, according to a statement from the German Interior Ministry.

"A direct exclusion of a particular 5G manufacturer is currently not legally possible and not planned," said a ministry spokesman, according to a CNBC translation. "The focus is on adapting the necessary security requirements so that the security of these networks will be guaranteed even if there are potentially untrustworthy manufacturers on the market."

The letter was sent Friday, the Journal said. This would be the first time the U.S. has explicitly threatened consequences against a country for using the Huawei's equipment, which has been the subject of heavy scrutiny from U.S. intelligence agencies that say the company is intimately connected to the Chinese government and intelligence agencies. Huawei continues to deny these claims, and has launched legal and marketing campaigns to defend itself.

A Huawei spokesperson and Grenell's office were not immediately available to comment.

Read the full Journal story here.