DANDONG: They met as children diving for fish when their countries, China and North Korea, touted a relationship as close as "lips and teeth" and when neither thought getting rich was glorious.

Now Chinese fisherman Xiao Yong smuggles food and items considered mundane in his own country to grateful old friends across the border, including a North Korean sweetheart he regrets he cannot marry.

The 31-year-old regularly crosses a muddy branch of the Yalu River separating northeast China from its famously hermetic neighbour, bribing his way past rifle-toting border guards with cash and cheap alcohol.

"My friends, now farmers and even soldiers, live bitter lives over there. It's like China under Mao Zedong," Yong said, standing astern while navigating his metal dinghy over the stream he knows so well.

"Some of them nearly starved to death during the famine in 1995, when people jumped over the border in waves. North Koreans, especially young girls and boys, still come over, even though it's a little harder now," he said.

The porous, unguarded border - in some places the river is no wider than a stone's throw - has proved irresistible to hundreds of thousands of North Koreans fleeing hunger, poverty and political persecution, aid workers say.

Activists say that up to 300,000 North Korean refugees are hiding in northeast China after fleeing hunger, poverty and repression in their Communist homeland.

Residents say security on the watery border has been tightened since 2002 when US officials said North Korea had confessed to building a secret nuclear programme in violation of an international agreement.

But it's easy for Chinese, including smugglers and human traffickers, to cross illegally into North Korea, they say, and this props up a thriving black-market border trade that helps keep the barren North Korean economy afloat.

Dandong natives such as laid-off factory worker Lao Zhou, whose picturesque home town draws tourists eager to spy on North Korea with telescopes, shake their heads when they talk about refugees.

"North Korean women make good wives. They are beautiful and hard-working," he said, echoing an oft-repeated view. "It doesn't cost much to buy a North Korean girl for a wife and just a few thousand kwai (hundreds of dollars) to get them a residency permit."

Refugees who cross the border near Dandong, which residents say is awash with North Korean agents posing as waiters and restaurant owners, usually make their way to the ethnic Korean autonomous region of Yanbian in northeast China.

Lucky ones are taken in by kind families, many of them Christian, and melt into the fabric of a familiar society speaking traditional Korean, a dialect their South Korean cousins find quaint.-Reuters