North Korea fully reopened the border Tuesday to South Koreans commuting to jobs at factories in a northern economic zone after four days of restrictions, South Korean officials said. Two border shutdowns in a week had stranded hundreds of South Koreans who work in Kaesong but live in South Korea, and left factories in the industrial complex with no new deliveries of raw materials for days. After partially opening the border Monday after a three-day shutdown, the North Korean military relayed a letter Tuesday saying it would fully reopen the border to Kaesong workers, Unification Ministry spokeswoman Lee Jong-joo was quoted as saying in Seoul. About 280 South Koreans crossed into Kaesong while 200 others returned home, and some 100 others chose to spend the night in the enclave, the ministry said.