One of the specialisms of the U.S. is to create extraterritorial legislation that enable procedures against non-U.S. parties by non-U.S. plaintiffs. In 2016 the Justice Against Sponsors of Terrorism Act (JASTA) was adopted (read introductory blogs in Dutch 1, 2).
According to an article in the NYT relatives of people killed and wounded in Afghanistan have started procedures against major banks, including European banks. The accusation is that these banks provided accounts and other banking functions to entities and individuals who they knew were aiding terrorist networks. According to the article there were no services provided directly to known terrorists; the claims are based on indirect relationships.
If the procedures succeed, it will probably cause banks to become even more frightened than they already are to provide services to foreign customers; de-risking and exclusion will increase and international trade will be hampered.