BEIJING: China said on Tuesday that North Korean border guards shot dead three Chinese citizens last week and that Beijing had protested to Pyongyang in a rare sour note between the close allies. The incident on Friday also left one person injured, foreign ministry spokesman Qin Gang said at a regular media briefing.“On the morning of June 4, some residents of Dandong city of Liaoning province were shot by DPRK (North Korean) border guards on suspicion of crossing the border for trade activities, leaving three dead and one injured,” the spokesman said. “After the incident, China attached great importance to it and immediately raised solemn representations to the DPRK.” He said the case was being investigated and gave no further details, while China’s state-controlled media has carried virtually nothing on the incident. Dandong is a Chinese border city through which much of the two nations’ trade is funneled. The incident comes amid heightened tensions on the Korean peninsula and closer scrutiny of China’s relations with Pyongyang after South Korea blamed the North for sinking one of its warships in March, killing 46 sailors. With US support, South Korea has called for UN action against North Korea over the sinking of the Cheonan and is seeking Chinese backing as well.Seoul’s Vice Foreign Minister Chun Yung-Woo arrived in China on Tuesday to seek Beijing’s support for a UN censure of North Korea. Pyongyang has rejected the charges and threatened war if any retaliation is taken. Beijing typically treads lightly in public comments about its unpredictable neighbour and instances of public discord between the two are rare. China provides vital economic and diplomatic support to the impoverished North, motivated experts say by Beijing’s fear the hardline communist regime could collapse, possibly sending millions of refugees across the border. Chinese leaders honoured North Korean leader Kim Jong-Il with the red-carpet treatment during a visit by Kim last month, but Beijing’s support has been tested by the Cheonan incident. An international group of investigators concluded last month that the ship was sunk by a North Korean torpedo, a finding that triggered international condemnation of Pyongyang. Beijing, however, has issued only mild calls for restraint.