Taiwanese President Lai Ching-te has postponed an official trip to Eswatini, the democratic island’s only diplomatic ally in Africa, after several countries revoked overflight permits following “intense pressure” from China, a senior aide said Tuesday.

China claims Taiwan is part of its territory and opposes the self-governed island’s participation in international organizations and exchanges with other countries.

Lai was due to visit Eswatini from April 22 to 26 for the 40th anniversary of King Mswati III’s accession and his 58th birthday.