Vietnamese users of Facebook were outraged last week to discover a map on the social media platform that depicted the Paracel and Spratly islands in the South China Sea as Chinese territory, even though Vietnam also has territorial claims in both island chains.

The Vietnamese government asked Facebook to correct the “misinformation about sovereignty” contained in the map, which was part of Facebook’s advertising toolset. Vietnam, China, and the Philippines contest ownership of islands in the Paracels, while Vietnam and China fought a naval battle over the Spratlys in the late Eighties.

China claims ownership of almost the entire South China Sea and disregards international court rulings to the contrary. The Chinese have used economic threats to bully foreign companies into censoring challenges to their territorial claims, even when they are as frivolous as the outline of China on a T-shirt.

Facebook representatives said there was “confusion” about the map and called it a “technical error without political intention.”

Facebook is enormously popular in Vietnam, boasting over 58 million active users, so the South China Sea map was quickly spotted and the backlash was considerable. Vietnamese users did more than just complain about the map; some business owners temporarily canceled their advertising in protest.

Facebook appeared to address the problem on Monday by completely removing the Paracel and Spratly Islands from its map. The Vietnamese Ministry of Information and Communications appeared content with this resolution and commended Facebook for its prompt attention, but a ministry official said a formal apology was still expected, along with measures to ensure that China will not be able to use the “incorrect” map as evidence for its territorial claims.