Vietnam pulled out all the stops this week for a visit from China's expected future leader _ including flags with an extra star.
The gaffe came during a welcoming ceremony for Chinese Vice President Xi Jinping in Hanoi on Wednesday when children waved flags decorated with six stars.
China's flag has only five stars _ one big star surrounded by four smaller ones.
Chinese Foreign Ministry spokesman Liu Weimin told reporters Friday that Vietnam had told the Chinese Embassy in Hanoi that it was "a technical error."
Relations between the countries have been strained over competing claims in the potentially oil-rich South China Sea. Vietnam and China signed cooperation agreements on youth affairs and health during Xi's visit.