There have been no arrests in the $50 million diamond heist at Brussels' international airport yesterday, when eight gunmen stole 120 packages from the plane's hold without a single gunshot.

The incident took less than five minutes Monday night from a plane, minutes away from takeoff. The men dressed in "dark police clothing" drove up to a Helvetic jet in cars with flashing lights, hold up the pilot and security officials on the plane.

"It was a well prepared operation. Robbers knew exactly when Brinks diamond and jewelry services truck would load" Ine Vanwymersch, told ABC News.

According to local media reports the robbers stole "rough diamonds" and according to an expert "it is virtually impossible to trace the stolen diamonds, whether rough or polished."

Harry Levy, president of London Diamond Bourse, said, "The actual diamonds themselves would probably fit in a shoebox."

The robbery is buzzing through the diamond industry centered in nearby Antwerp, world's largest diamond-trading center.

Retired FBI agent Bill Rehder said the theft is a "huge blip on the radar."

"You can almost liken it to the meteor that hit in Russia," he said, referring to the meteorite that exploded last week over central Russia, injuring hundreds. "These things happen so infrequently, but when they do happen, it's a huge story."

It seems the thieves knew their way around as the planned heist barely took five minutes to execute as the diamonds were being loaded onto a plane bound for Switzerland.

"This is causing quite some unrest," a Diamond Center spokeswoman says. "It was incredible how easily it all went. This is worrying in terms of competitiveness, since other diamond centers are ready to pounce and take over our position."