On March 22, 2021, a diplomatic incident started after the Philippines filed a diplomatic protest against China due to the presence of more than 200 Chinese fishing vessels at Whitsun Reef as early as March 7, 2021. The reef is part of the contested Spratly Islands in the South China Sea. Over time, the Chinese presence in the Whitsun Reef declined. However, the ships' dispersal to other parts of the Spratly Islands prolonged diplomatic tensions.