BOSTON — Climate activists from Extinction Rebellion Boston shut down a busy Back Bay intersection Monday morning by welding one of their members to a metal tube attached to a pink Toyota Corolla in the middle of the road — forcing Boston Police and fire crews to haul out power saws to cut the car apart and clear traffic.

The blockade went up at the intersection of Dartmouth Street and St. James Avenue near Copley Square, directly outside the Westin Copley Place hotel where the Northeast LDC Gas Forum — an annual fossil-fuel industry conference — is scheduled to run June 8 to 10.

The bright pink Corolla, plastered with a banner reading "GAS IS BAD FOR MASS" and the Extinction Rebellion hourglass logo, sat sideways across the intersection while officers and firefighters in full bunker gear surrounded it. At least one activist had welded herself to a steel pole bolted to the vehicle. Others chained themselves to large pink barrels, holding signs that read "Road Closed for 'Natural' Gas Conference."

With no other way to separate the woman welded to the car, Boston Police and Boston Fire crews used reciprocating saws to cut through the metal pole and free her from the vehicle. Other officers worked the barrels — known to organizers as "sleeping dragons," locked-arm devices that have to be cut open with power tools to extract the protesters inside.

All five of the welded and chained protesters were eventually arrested, the Boston Police Department later confirmed in an official account of the morning. Boston Police issued a public traffic advisory Monday warning commuters and pedestrians to avoid the area, citing the protest's impact on "vehicular and pedestrian traffic" through the heart of Back Bay.

The first units on scene were Boston Police officers from District D-4 (South End), responding to a 7:44 a.m. radio call about protesters gathering at Dartmouth Street and St. James Avenue, the department said. By the time they arrived, the road was already shut down.

Officers made several attempts to talk the activists into clearing the road for what BPD called "increasingly inconvenienced commuters." A few protesters complied and moved to the sidewalk. The ones welded into the barrels did not — and two of them then escalated, walking to the back of the pink sedan and inserting their arms into a second set of welded steel tubes bolted to the trunk. A fifth activist allegedly inserted herself between firefighters and the chained demonstrators during the extraction, BPD said, in what the department described as an attempt to obstruct the operation.

All five were eventually taken into custody:

All five are expected to be arraigned in Boston Municipal Court on charges of unlawful assembly, disturbing the peace, disorderly conduct, and resisting arrest. Pancoast faces an additional charge of wrongful interference with the operation of a school bus.

The Northeast LDC Gas Forum is a private-industry conference attended by executives of local gas distribution companies — Local Distribution Companies, or LDCs — who set buying and infrastructure plans for natural-gas service across the Northeast.

The group described its action as "a peaceful, non-violent, non-destructive act of civil disobedience." Police, Fire and EMS crews who spent the morning cutting protesters off welded steel and out of locked barrels in the middle of rush hour are not on the record either way.

This is a developing story.