Chinese customs authorities in Shandong province have reportedly confiscated 60,000 maps destined for export after alleging they contained “serious mistakes” related to the depiction of Taiwan and the South China Sea, according to the BBC. It is presumed this means they identify Taiwan as an independent nation

Officials said the maps failed to correctly mark Taiwan, which Beijing regards as a province of China despite the island’s self-governing status, and omitted several disputed islands in the South China Sea the BBC report adds. The products, described as “problematic”, were deemed to “endanger national unity, sovereignty and territorial integrity”, according to a statement from Chinese authorities cited by the broadcaster.

Beijing maintains that all maps published or distributed in China, including those intended for overseas sale, must conform to its official territorial claims. These include the controversial nine-dash line, which demarcates Beijing’s assertion of sovereignty over nearly the entire South China Sea, an area also claimed in part by Taiwan, the Philippines, Vietnam, Malaysia and Brunei.

Authorities said the seized maps not only lacked the nine-dash line but also failed to show the maritime boundary between China and Japan. They added that Taiwan had been “mislabelled”, though they did not specify in what way.

Taiwan, which has its own democratically elected government, currency, military and constitution, rejects Beijing’s sovereignty claims. China, however, insists the island is part of its territory and has not ruled out the use of force to bring it under its control.

The South China Sea meanwhile remains a perennial flashpoint with China frequently clashing with other nations in the region – most recently by way of a Chinese vessel being accused of deliberately ramming and using water cannon against a Philippine government ship.