Visitors taking snapshots of messages calling for reunification at an observatory near the Demilitarised Zone (DMZ) separating the two Koreas on the island of Ganghwa, west of Seoul, on Tuesday. In the six months to June, 593 Northerners escaping poverty and persecution entered South Korea, down 20.8 per cent from the same period last year, statistics by Seoul's Unification Ministry showed. The sharp decline came as Pyongyang strengthened controls on its border with China, officials said yesterday.