Security concerns related to Chinese investments in overseas ports are mounting as the country’s firms acquire more stakes at shipping hubs around the world and geopolitical tensions rise.

Chinese companies have expanded investments at foreign ports in recent years and now run major container terminals in locations including Belgium, Israel, Spain, Sri Lanka and the United Arab Emirates. All told, Chinese and Hong Kong-based firms hold stakes in terminal leases or concessions at 95 foreign ports, according to research by Isaac B. Kardon of the U.S. Naval War College and Wendy Leutert of Indiana University.