Congress opened a new front in the government’s antitrust probe of giant technology firms, with House lawmakers on Friday demanding emails and other records from some of the industry’s top chief executives as they look for evidence of anticompetitive behavior.

The requests from House Judiciary Committee leaders from both parties to Amazon.com Inc., Facebook Inc., Apple Inc. and Alphabet Inc., owner of Google, set up potential conflicts between tech leaders protective of their business tactics and lawmakers who want to scour...