Jūnduì zài chéngshì zhōuwéi jiànlì le fēngsuǒxiàn.
The military established a blockade line around the city.
Tips
usage
封锁线 combines 封锁 (to blockade / seal off) with 线 (line). It is used for both military cordons and civilian police perimeters. Compare 警戒线 (police line), which is more common in civilian contexts.
