China has quietly built up a significant military force in Hong Kong in the face of escalating pro-democracy protests and a significant landmark date for Beijing, Reuters reports. The buildup to as many as 12,000 troops has been disguised as a regular rotation of China’s People’s Liberation Army forces that have been kept in Hong Kong since the city was handed over from Britain in 1997. But Reuters reports it spoke to several sources within the military who say that recent “rotations” were actually “reinforcements” and that no troops were returned to the mainland. Reuters could not confirm whether the reinforcements are part of a planned crackdown on the demonstrations that have rocked the city for 17 weeks. Some sources also said that members of China’s elite paramilitary People’s Armed Police had been deployed to the city. China will celebrate its 70th anniversary of the founding of the People’s Republic of China on Oct. 1, when widespread protests are expected.