NANNING, Jan. 12  -- A total of 5,471 illegal immigrants, mainly from Vietnam, were intercepted by border police in south China's Guangxi Zhuang Autonomous Region in 2014, up 20 percent from the previous year, local authorities said Monday.

About 45 percent of the illegal immigrants, ranging in age from 16 to 45, planned to cross the border to work in the booming provinces of Guangdong and Fujian for higher salaries, according to the Guangxi border police.

About 47 percent of them planned to work in border areas and the rest planned to work in cities in Guangxi.

Most of the illegal immigrants were repatriated, according to the border police.

December to April is the harvest season for sugarcane in Guangxi, which has faced a labor shortage, and some of the illegal immigrants planned to harvest sugarcane in border areas.