A leading US maker of identification cards has raised national security concerns after French defence electronics maker Safran submitted a rival, unsolicited bid for Digimarc, another US ID card company that has contracts with the Department of Homeland Security.

Robert LaPenta, chairman and chief executive of L-1 Identity Solutions, raised doubts about whether Safran could win US government approval for its proposed $300m (€193m, £152m) all cash bid for Digimarc, citing the French government's 30 per cent ownership interest in the company.