As the South Korean forces and their allies got closer to the Chinese border while invading North Korea, Chinese communist "volunteers" joined with the North Korean forces. Mao Zedong, leader of the Chinese, set up the People's Volunteer Army (PVA), which allowed Chinese citizens to enlist in war against South Korea. With the help of the Chinese, the North Koreans were able to push the South Koreans, once again, back down below the 38th parallel. The North Korean forces captured Seoul and continued advancing South.