'Black Lives Matter' protesters block Boston highway during morning rush

At least 23 people were arrested Thursday after activists protesting what they call "police and state violence against black people" chained themselves to barriers and blocked a busy Boston area highway at the height of the morning commute.

State police say in response to the Thursday morning protest, they shut down Interstate 93 north at East Milton Square south of the city, and I-93 south at Mystic Avenue north of the city. Seventeen protesters were arrested on I-93 south and six on I-93 north, MyFoxBoston.com reports.

State police later tweeted that two of the four northbound lanes at East Milton Square reopened to traffic and all the southbound lanes were reopened just after 8 a.m.

Authorities said they needed power saws to free some protesters who had chained barrels to themselves.

The Boston contingent of Black Lives Matter said in a statement that the protest was intended to "to confront white complacency in the systemic oppression of black people in Boston."

"Today, our nonviolent direct action is meant to expose the reality that Boston is a city where white commuters and students use the city and leave, while black and brown communities are targeted by police, exploited, and displaced," protester Katie Seitz said in a statement.

The Associated Press contributed to this report.