A South Korean lawmaker claimed Monday four more North Korean defectors had been detained by Chinese authorities in the central city of Zhengzhou while fleeing their impoverished homeland, raising the number of defectors believed to be in custody to 34.

   Rep. Park Sun-young of the minor opposition Liberty Forward Party had earlier said five groups totaling 30 North Korean asylum seekers have been detained in China since earlier this month in a tightened crackdown on defectors near the border between the two nations.

   Citing anonymous sources based in China, Park said a group of two women, one man and a child were caught by local authorities while fleeing from the northeastern city of Shenyang to Zhengzhou on foot.

   "North Korean defectors are at a loss as Chinese authorities have reinforced a crackdown (on them)," Park said.

   South Korea's foreign ministry did not immediately confirm the total number of North Korean defectors in China or how many are facing repatriation to the communist state.

   Seoul has urged China not to send back North Koreans on a humanitarian basis and plans to hold talks with Beijing to discuss the issue later this month.

   In response to the calls, Chinese foreign ministry spokeswoman Hong Lei told reporters that Beijing is handling the issue in line with domestic and international laws and humanitarian principles.

   In Seoul on Monday, the local branch of rights group Amnesty International sent a letter to the Chinese embassy, demanding China not to repatriate the North Korean defectors.

   Tens of thousands of North Korean defectors are believed to be hiding in China, hoping to travel to Thailand or other Southeast Asian countries before resettling in South Korea, home to more than 23,000 North Korean defectors.

   North Korean defectors face harsh punishments and even execution after being repatriated from China, according to defectors in South Korea and human rights activists. (Yonhap News)