A spokesman for the Yemen Embassy in Washington told CBN News that his government is working around the clock to track down six missing Christian missionaries who disappeared last month.

Authorities discovered the dead bodies of three other members of the group, but five Germans and one British citizen have yet to be found.

"We're using helicopters with night vision equipment to look for them at night," spokesman Mohammed Albasha said. "We're using our counter-terrorism special forces. German law enforcement, Korean law enforcement. We're working even with the U.S. government to track them down."

"Unfortunately, we have not succeeded. But we're hoping that if these six hostages are still out there, we will be able to free them," he said.

It's believed that if alive, the remaining hostages are being held in mountainous terrain in northern Yemen, near the Saudi border. 

As for the kidnappers, Albasha says Yemen will treat them with "an iron fist" if they are apprehended.