Europol's director says terror cells are still actively plotting attacks against Europe.

Robert Wainwright, director of the European police organization, said a drop in attacks, coupled with intelligence that had thwarted major plots, masked the ongoing threat.

His remarks Thursday come amid news of a terror threat against Britain, France and Germany. The threat was intercepted in Pakistan by US intelligence officials, sparking a surge in drone missile strikes near the border with Afghanistan.

Wainwright was speaking at a security conference in Brussels.

Officials at the conference also warned of security threats coming from African countries.

Ronald K. Noble, Interpol's Secretary General, says a rise in drug trafficking had fueled violence and instability. More than a quarter of all cocaine now passes through Africa from South America.