Number of N . K . defectors falls 18 . 7 pct on - year in Q 1 : data SEOUL , April 5 ( Yonhap ) -- The number of North Koreans escaping to South Korea declined 18 . 7 percent in the first quarter from a year earlier , government data showed Wednesday , as the North is seen as strengthening border control . A total of 278 North Koreans came to South Korea in the January - March period , compared with 342 tallied the year earlier , according to preliminary data by the Ministry of Unification . The latest tally marked the smallest number of quarterly defectors since North Korean leader Kim Jong - un assumed power in late 2011 . Since the second half of 2015 , North Korea has bolstered border control and set up high - tension wires around the Tumen River , which flows between the North and China to prevent more North Koreans from escaping the country , according to a report by the Korea Institute for National Unification ( KINU ) . Some experts said that China may have beefed up surveillance along the border with North Korea in an expression of its anger against Seoul and Washington ' s ongoing deployment of an advanced U . S . missile defense system . China has sent scores of tanks into areas bordering North Korea in an apparent bid to strengthen border control , according to sources . The Seoul government remained cautious about the reading of the latest tally . " In the first two months of 2017 , the number of North Koreans coming to the South fell on - year . But as those people rose in March from a year ago , it is hard to prejudge ( what the data means ) , " a ministry official said . The number of North Korean defectors surpassed the 30 , 000 mark in November last year . Last year , the pace of annual growth of the North defectors picked up for the first time since 2011 . A rise in defections was largely attributable to Kim ' s move to strengthen his iron - fisted rule and the toughening of international sanctions , the government earlier said . sooyeon @ yna . co . kr ( END )