Harassment and violence have become common outside abortion clinics over the decades since the 1973 ruling legalizing abortion.

Now providers and some in law enforcement are preparing for an increase in violence once the Supreme Court rules in a case that could end Roe v. Wade.

They anticipate protests, harassment and other violence will increase in states where abortion remains legal.

The National Abortion Federation and the hundreds of abortion clinics it represents have been on "heightened alert" since the opinion leaked.

The Department of Homeland Security has warned violence is likely to increase on both sides.