The research group said an investigation had shown that nine out of 10 carriers involved in illicit weapons trading had also been used by the European Union, United Nations agencies, NATO members and other non-profit groups sending aid to Africa.

In addition to arms, questionable transports include illegal drugs, diamonds and other precious minerals, according to the report.

In Sudan, "all companies that have been listed by the UN for illicit arms transfers have been used for humanitarian aid," report co-author Hugh Griffiths told Associated Press.

Europe urged to act

The peace institute called on Europe to take the lead in developing a code of conduct for air cargo transporters. The group recommended the EU use "existing air safety regulations" to put companies involved in illicit activities out of business.

"Our research shows that companies named in arms trafficking-related reports have poor safety records. Safety regulations represent their Achilles heel," co-author Mark Bromley said.

The report called on UN agencies, governments and NGOs to make humanitarian aid and peacekeeping contracts conditional on adherence to an ethical transportation code.

Swedish International Development Cooperation Minister Gunilla Carlsson called the report findings "very disturbing" and said "immediate action" was needed. Carlsson said Sweden would begin working to put the institute's recommendations into place.

The Swedish parliament created SIPRI as an independent foundation in 1966. SIPRI has for decades tracked global arms spending and publishes regular reports on its findings.