"Please, get out of here," the man screamed in English, flailing his arms. "I don't want to die. I don't want to die. I know that your life is important, but my life is important."

A South Korean television news station, YTN, identified the hostage as Kim Sun-il, 33, an employee of a South Korean company called Arab Trading. It said he was captured in the Fallujah area.

The video came two days after news of the beheading of American hostage Paul Johnson by Saudi militants, and an announcement Friday by South Korea that it will send 3,000 soldiers to northern Iraq beginning in early August. Once the deployment is complete, South Korea will be the largest coalition partner after the United States and Britain.

After showing the hostage's plea, the tape showed him kneeling in front of three masked men, one of them armed with a Kalashnikov. The man standing in the middle read a statement in Arabic.

"Our message to the South Korean government and the Korean people: We first demand you withdraw your forces from our lands and not send more of your forces to this land. Otherwise, we will send to you the head of this Korean, and we will follow it by the heads of your other soldiers."

The statement gave Seoul 24 hours starting from sunset Sunday to meet its demand.

The two-minute videotape was mailed to the Al-Jazeera bureau in Baghdad.

The group identified itself as a group led by Abu Musab al-Zarqawi.

On Saturday, Seoul warned its people not to travel to Iraq, saying its decision to send troops might prompt terror attacks on South Koreans.

That warning came amid news of the beheading of the American hostage, Paul Johnson, although it did not mention the incident.

"At this time, we cannot rule out the possibility of harm to our nationals, following the official announcement of the additional troop dispatch to Iraq," Foreign Ministry spokesman Shin Bong-kil said in a statement.

"The government urges the people to refrain from visiting Iraq," it said.

South Korea plans to send 900 troops to Kurdish-controlled Irbil in early August, followed by about 1,100 troops between late August and early September. An additional 1,000 soldiers will travel to Iraq later.

South Korea already has 600 military medics and engineers in the southern Iraqi city of Nasiriyah.