Chinese customs officers in eastern Shandong province have seized 60,000 maps that mislabelled the self-governed island of Taiwan, which Beijing claims as part of its territory.

The maps, authorities said, also omitted important islands in the South China Sea, where Beijing's claims overlap with those of its neighbors, including the Philippines and Vietnam.

The problematic maps, meant for export, cannot be sold because they endanger national unity, sovereignty, and territorial integrity of China, authorities said.

Maps are a sensitive topic for China and its rivals for reefs, islands, and outcrops in the South China Sea.

China Customs stated that the maps did not contain the nine-dash line, which demarcates Beijing's claims over nearly the entire South China Sea, extending hundreds of miles from its southernmost province of Hainan.

Moreover, the seized maps failed to mark the maritime boundary between China and Japan, authorities noted.

In the context of cross-strait relations, Taiwan sees itself as distinct from the Chinese mainland, functioning with its own constitution and democratically elected governance, while China considers Taiwan its territory and has not ruled out potential force to assert control.

Tensions in the South China Sea have recently escalated, with allegations of aggressive encounters between Chinese and Philippine vessels.

The Philippines accused a Chinese ship of ramming and using water cannons against a Philippine vessel, which China countered by stating that the Philippine ship ignored warnings.

Regional sensitivities around mapping were highlighted when the 2023 Barbie movie was banned in Vietnam and censored in the Philippines for showing a map including the contentious nine-dash line.

The confiscation of maps deemed problematic by customs is not an uncommon event in China; however, the current seizure is notable for its scale. Earlier this year, 143 nautical charts with border inaccuracies were also confiscated by customs in Qingdao.