The German government says it is growing increasingly concerned about two engineers held hostage in Iraq after a new video of the men and their captors was released.Yesterday the group holding Rene Braeunlich and Thomas Nitzschke said it would kill them in 72 hours unless Germany closes its embassy in Baghdad. Foreign Minister Frank-Walter Steinmeier has renewed an appeal for the pair to be freed. He said everything was being done to bring them home safe and sound. They were seized last Tuesday at an industrial compound near the town Baiji. The government has set up a special crisis centre to deal with the situation.But no details have been given about what exactly is being done to secure the men’s release. In December, a German archeologist who had been held for three weeks was released by her kidnappers. Berlin refused to comment on speculation that a ransom was paid.