SEOUL, June 24: Anti-war passions flared on Thursday as South Korean activists vowed to block the dispatch of more troops to Iraq and the government banned a video of the beheading of a Korean national.

South Korean anger was triggered by the brutal killing of 33-year-old hostage Kim Sun-Il by his captors after President Roh Moo-Hyun refused their demand to cancel the deployment of more than 3,000 extra South Korean troops to Iraq starting in August.

US President George Bush sent a letter of condolence to Mr Roh on Thursday, expressing gratitude for the courage shown by the Korean people in "our historic joint struggle against terrorism", Mr Roh's aides said.

A candlelit vigil near the US embassy in central Seoul, which has become a daily routine since Seoul announced the troops deployment on Friday last week, drew some 300 protestors on Thursday, who chanted: "No war, no deployment."

Pro- and anti-war demonstrators took to the streets of Seoul and anti-war groups said they would stage rallies on Saturday in cities across the country. "We will stage an all-out struggle by our members to stop the dispatch of troops," said the umbrella Korean Confederation of Trade Unions, which groups some 500,000 workers.

Pilots at South Korea's two commercial airlines, Korean Air and Asiana, said in a statement they would boycott flights carrying troops or equipment to Iraq. South Korea agreed last year to a US request to deploy troops in Iraq, a decision ratified by parliament in February.

Analysts said the killing of Mr Kim further polarized the country between opponents and supporters of the US. "Opposition to the war and the troop dispatch will grow," said political science professor Lee Chung-Min at Hankook University of Foreign Studies.

But he said there was now no going back for Mr Roh, who would compromise his leadership if he reversed the troop decision. Several pro-US activists on Thursday torched a portrait of Abu Mussab al Zarqawi, the Al Qaeda linked militant who leads the group who beheaded Mr Kim.

Anti-Arab sentiment was also apparent as police stepped up security to protect South Korea's small community of around 30,000 Muslims after some 40 callers threatened to blow up Seoul's main mosque.

The anger of the anti-war activists focused on the government for standing firm on the troop dispatch instead of bowing to the militants' demand, with some directing their rage at the foreign ministry, accusing it of bungling the attempt to free Mr Kim.

South Korea's National Assembly held a hearing into the handling of the failed release effort amid reports here that diplomats had been informed of Mr Kim's abduction earlier than previously acknowledged.

Media reports said that Kim Sun-Il was abducted on May 31, rather than June 15, and that diplomats were informed before militants issued their demands through Al Jazeera, the Qatar-based satellite news channel, on Sunday.

Initially, the foreign ministry said it knew nothing of the kidnapping until it saw the Al Jazeera broadcast. Mr Kim's body was found dumped on a road west of Baghdad on Tuesday after his beheading.

Seeking to cool passions, the South Korean government said it would punish Internet service providers who showed graphic video footage of the beheading. The Ministry of Information and Communication shut down a local website showing images of the killing, Yonhap news agency said.

A video showing Mr Kim before the killing was aired by Al Jazeera. But the network refrained from showing the beheading saying the scene could cause anguish for viewers. -AFP