US immigration authorities have arrested 36 foreigners, including some Ghanaians, who were working illegally for a contractor of the Department of Defence, NASA and the Department of Energy.

US Immigration and Customs Enforcement (ICE) agents, in conjunction with the Defence Criminal Investigative Service and the Social Security Administration, made the arrests in North Carolina on October 18, ICE said in a release on Friday.

The workers, who hailed from Pakistan, Congo, Gambia, Guatemala, Indonesia, Israel, Kenya, Mexico, Pakistan and Togo, were nabbed from the work site of Cree, Inc, a manufacturer of electronic devices using silicon carbide semiconductor technology and other high technology devices. Eight of those arrested worked for Cree and others for two of its subcontractors.

Agents found that many of the illegal workers had used invalid, altered or falsified documents to illegally obtain employment, and they continue to investigate the entirety of the circumstances surrounding their employment, ICE said.

Tom O'Connell, Resident Agent-in-Charge for ICE in Raleigh, said: "Unauthorised workers pose potential homeland security threats. Not only is their identity in question, they may also be vulnerable to exploitation by terrorists and other criminals."

All of those arrested were placed into removal proceedings. An independent immigration judge will now hear their deportation cases.

Cree Inc is not a subject of the investigation and is cooperating in the investigation, ICE said.