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 neighbours, 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 said that the maps also did not contain the nine-dash line, which demarcates Beijing's claim over nearly the entire South China Sea. The line comprises nine dashes which extend hundreds of miles south and east from its most southerly province of Hainan.
The seized maps also did not mark the maritime boundary between China and Japan, authorities said. Authorities noted that the maps mislabelled Taiwan province without specifying the nature of the mislabelling.
China sees self-ruled Taiwan as its territory and has not ruled out the use of force to take the island. However, Taiwan considers itself distinct from the Chinese mainland, having its own constitution and democratically-elected leaders.
Tensions in the South China Sea escalate periodically, with recent encounters between Chinese and Philippine ships leading to accusations against each party. Manila accused a Chinese ship of deliberately ramming and firing its water cannon at a Philippine government vessel, while Beijing countered that the Philippine vessel ignored dangerous warnings.
The Philippines and Vietnam are particularly sensitive to how the South China Sea is depicted in maps; the Barbie movie from 2023 was banned in Vietnam and censored in the Philippines for showing a South China Sea map that included the controversial nine-dash line.
China's statement did not specify where the seized maps were intended for sale. Customs seizures of problematic maps are not uncommon, though the number seized in Shandong far surpasses previous confiscations.
In March, customs officers at an airport in Qingdao seized 143 nautical charts that contained errors regarding national borders. In August, customs in Hebei seized two maps with a misdrawing of the Tibetan border.