"The German hostage Rudolf B. ... urged Germany and the United States to pull out their forces from Afghanistan and urged his country to help save his life and secure his return to his homeland and family," an Al Jazeera presenter said.

The voice of the hostage was inaudible in the video.

The man, wearing a thick jacket and pair of jeans, was shown speaking into the camera in a mountainous landscape surrounded by masked men pointing guns at him.

Images said to date from Saturday

German Foreign Ministry spokesman Martin Jäger described the video as a "document of intimidation" and said experts would analyze and evaluate the images.

Early Wednesday, however, Germany's Spiegel Online Web site reported that the video was several days old.

Spiegel Online said the video images broadcast by Al Jazeera had been stored on a memory stick. The digital information on the memory device revealed that the last time it was altered was the previous Saturday.

Experts recognize jacket

Experts from the emergency task force in the region said that in the video, the abducted engineer was wearing a fleece jacket that a negotiator had sent to him in the mountains from the German
embassy in Kabul at the end of last week.

The 62-year-old German engineer was kidnapped on July 18 along with a colleague. The other man's body was found several days later with bullet wounds.

The video also showed four Afghans taken captive with the German, asking the Afghan government to give into the kidnappers' demands.

Korean crisis continues

Meanwhile, talks aimed at freeing 21 South Korean hostages resumed Wednesday after no overnight breakthrough as a deadline set by their Taliban abductors loomed, negotiators said.

The militants have threatened to kill more hostages after murdering one man late Monday following the expiry of other deadlines.

He was the second of the Christian aid workers to be killed since the group's July 19 abduction in the southern province of Ghazni.