But human rights groups maintain that China uses counterterrorism efforts as a pretext to suppress Uighurs, who often resent the restriction of religious and cultural expression. And China's increased economic efforts in the region have stirred resentment amongst Uighurs, who complain that the heavy influx of Han Chinese has taken jobs from Uighur natives. After the 2013 Tiananmen attack, Uighurs blamed the violence on cultural repression, corruption, and police abuses. The 2014 knife attack at a Kunming train station, labeled a Xinjiang separatist "terrorist attack" by the central government, triggered further concerns of discrimination.