U.S. and European moves to sanction two adult daughters of Russian President Vladimir Putin cast a spotlight on a family shrouded for years in secrecy.

The White House said Wednesday it would sanction Mr. Putin’s two children from his now-ended marriage to a former Aeroflot cabin crew member, according to U.S. officials. The European Union, meanwhile, is set to make the same move following discussions among its 27 members, according to diplomats. The EU sanctions, expected to take effect by Friday, would entail a freeze of any assets held in the bloc and a ban on traveling to member countries.