The US looks to be tightening up its technology export restrictions on China following Huawei’s release of a new 5G smartphone using homemade chips, a feat many had thought it would not be capable of delivering.

Huawei launched the Mate 60 Pro without much fanfare at the end of August, but it caused a stir nonetheless because its very existence seemed to prove that Washington’s efforts to curb Chinese progress in advanced semiconductor technology weren’t entirely successful.

According to Nikkei Asia, two US lawmakers have now called for the government to close any loopholes in the technology export controls it has imposed on Chinese companies such as Huawei following the launch of the Mate 60 Pro.

Mike Gallagher, chairman of the House Select Committee on the Chinese Communist Party (CCP), is said to have pointed the finger at exemptions to the existing restrictions governing the export of semiconductor technology to the country, claiming these represent loopholes that allow Chinese companies to side-step the sanctions and access whatever technology they require.

Last week, Gallagher was reported to be calling for the US Commerce Department to end all technology exports to Huawei and Chinese chipmaker Semiconductor Manufacturing International Corporation (SMIC) after a teardown of the Mate 60 Pro revealed it is powered by a 7nm system-on-chip (SoC) from SMIC.

The chipmaker had previously been capable of producing only 14nm silicon at best, leading to accusations that it had been in breach of US technology restrictions.

“This chip likely could not be produced without US technology and t