SOFIA, Bulgaria (AP) — Bulgaria has joined other Balkan countries in signing an agreement with the United States on high-speed wireless network security aimed at excluding Chinese hardware providers.

Bulgaria joined North Macedonia and Kosovo, neighboring nations that also signed the “Clean Network” security agreement on Friday.

It is part of a Trump administration effort to exclude tech giant Huawei and other Chinese companies in 5G networks.

U.S. government officials have led a campaign across Europe and elsewhere against the inclusion of Huawei, which has been blacklisted for posing a threat to national security and using its technology to spy on behalf of the Chinese government.

China argues that the U.S. initiative is driven by commercial concerns.

The U.S. Embassy in Sofia said Bulgaria “joins a growing coalition of countries and companies committed to protecting their 5G networks from untrusted vendors.”

U.S. Under Secretary of State for Economic Growth Keith Krach said in a government video from Friday’s signing ceremony with Bulgaria that the agreement is vital to national security, economic prosperity and stability in the region.