MINNEAPOLIS --  Authorities might change their tactics at protests after the deaths of five officers at a Dallas demonstration over the recent police killings of black men.

In St. Paul, officers in riot gear met protesters who blocked Interstate 94 late Saturday. About 100 people were arrested in protests, and 21 officers and state troopers were hurt.

It was a contrast to their approach to protests outside the governor's mansion following motorist Philando Castile's shooting death Wednesday in the suburb of Falcon Heights.

Craig Lally, president of the union representing Los Angeles police officers, says he suspects changes will be made at departments across the country when it comes to staffing protests and similar events.

But Dallas Mayor Mike Rawlings says he doubts his city's protocol will significantly change.