The armed forces have transferred the acreage to the government to give back to its owners, but there have been delays.
Jilin-based Changchun Changsheng has meanwhile recalled its rabies vaccine amid safety concerns.
Only the children of high-ranking officials or wealthier families do not have to work, one source says.
Nguyen Hai Long, a resident of the Czech Republic, says he helped Vietnamese secret police grab Trinh Xuan Thanh, now serving two life terms in Vietnam.
