Kennedy, 18, was arrested along with 47 others for civil disobedience Wednesday outside the White House at a protest opposing the Keystone XL tar sands pipeline.
Conor’s father, Robert F. Kennedy Jr., was also arrested, as was the actress Daryl Hannah and Sierra Club executive director Michael Brune.
The protesters blocked a main thoroughfare in front of the White House and refused to move when asked by police. Both Kennedys were taken in handcuffs to a Park Police station. They were released after paying a fine.
Robert Kennedy posted a series of photos of the events on Twitter. “Handcuffed to White House gate in act of civil disobedience for climate change!” he wrote in one post. “Everyone is out of jail after protest!” he added later.
The Keystone XL pipeline would bring oil from Canada’s tar sands to the Gulf Coast of the U.S. The Environmental Protection Agency (EPA) has said it could boost annual U.S. carbon pollution emissions by up to 27.6 million metric tons.