China is extending its sway over an autonomous enclave run by Myanmar’s most powerful ethnic armed group, sources in the region told Reuters, bolstering Beijing’s role in the peace process that is the signature policy of Aung San Suu Kyi.

The “foreign policy” of the self-proclaimed Wa State is closely monitored by Beijing, senior officials in the administration run by the 30,000-strong United Wa State Army (UWSA) and its political wing said, with contact with Western governments, businesses or aid groups deemed particularly sensitive.

Official known to Myanmar as “Special Region 2”, the remote territory is the size of Belgium and home to 600,000 people. Largely closed to Westerners for decades, it was visited by Reuters in October.

China’s influence is quickly apparent, with street signs in Mandarin and Chinese businesses and banknotes ubiquitous in the self-proclaimed state’s capital, Pangsan, and other Wa towns that straddle the rugged border.