SEOUL, April 29 (Reuters) - South Korea's foreign ministry has voiced its concern to the Chinese ambassador in Seoul over violent incidents during the torch relay in the capital, and a police investigation is underway, an official said on Tuesday.

South Korean newspapers ran angry editorials denouncing Chinese students who hurled rocks at groups criticising Beijing, charging into lines of police, beating pro-Tibet protesters and kicking an elderly man.

The justice minister told a cabinet meeting Sunday's violence was "seriously regrettable".

On Monday, South Korea's foreign ministry lodged a complaint with the Chinese ambassador. Officials from the Chinese embassy were not immediately available for comment.

The global relay has endured the most tortuous journey of its history, beset by trouble from the moment protesters breached security at the torch-lighting ceremony at Ancient Olympia in Greece last month.

Subsequently, protesters have jostled the torchbearers in London, Paris and San Francisco, and shouted slogans denouncing Beijing's human rights record, especially in Tibet.

The protests have embarrassed China and prompted some Chinese to call for boycotts of Western businesses, and spurred patriotic Chinese abroad to rally behind Beijing during the relay's journey through Asia. On occasions the pro-Chinese supporters have outnumbered protesters.

In Seoul, thousands of the Chinese students were bussed in from around the country for pro-Beijing rallies in the heart of the city, which was swept up in a sea of red Chinese flags. For the most part, the rallies were spirited but peaceful.

Internet message boards in South Korea, one of the world's most wired countries, have been flooded with comments saying the pro-Beijing display was in bad taste, did little to send any message of peace and soured the appetite for the Olympics.

"What right do these people have to travel in hordes in a foreign capital, hurling punches and launching kicks at others," the Chosun Ilbo, South Korea's biggest daily, said in an editorial. (Reporting by Jon Herskovitz and Jack Kim; Editing by Jonathan Thatcher and Jeremy Laurence) ("Countdown to Beijing Olympics" blog at http://blogs.reuters.com/china)

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