The video shows Rene Bräunlich and Thomas Nitzschke on the ground in front of four masked and armed kidnappers and was dated Jan. 24, the day the two engineers were kidnapped near the city Baiji.

The two men, originally from Leipzig, gave their names, the name of the gas installation company they work for, Cryotec, then appealed to the German government to do everything it could to secure their release, according to German public broadcaster ZDF, which received a copy of the video from Al Jazeera.

"The pictures which reach us from Iraq this morning are shocking," said German Foreign Minister Frank-Walter Steinmeier said Friday. "We call for them to be released as soon as possible."

The German Foreign Ministry's crisis center staff is evaluating the video's authenticity. Al Jazeera said a group calling itself Ansar al-Tawheed wal Sunnah produced the videotape and reported that the kidnappers did not make any demands.

Some relief

"It is good to know that he is alive," a friend of Bräunlich's told Germany's dpa newsagency. "That's the most important thing."

Bräunlich's soccer team, SV Grün-Weiss Miltitz, is collecting donations to provide help for his family, including psychological counseling.

The team posted a message on its website: "Rene, you are in our thoughts."

Cryotec, the German gas installation company which employed the two men, has rejected criticism that it had failed to protect its workers.

"They are biased statements made without knowledge of the circumstances," Cryotec chairman Peter Bienert told Friday's edition of the Leipziger Volkszeitung newspaper.

US and Iraqi forces have been searching for the two men and in the past two days 20 suspected insurgents have been arrested in the area.

More than 250 foreigners have been taken hostage in Iraq since the 2003 US-led invasion began.