A bipartisan group of federal lawmakers has raised the possibility of prosecuting pipeline saboteurs and violent anti-oil and gas activists as domestic terrorists, according to a letter sent to Attorney General Jeff Sessions Monday.

Led by Rep. Ken Buck (R-CO), a group more than 80 members of the House of Representatives — mostly Republicans — highlighted reports of attempts to vandalize oil and natural gas pipelines, and of calls to violence against the oil and gas industry.

“In April, a newspaper in Colorado went as far as publishing a letter to the editor that stated, ‘If the oil and gas industry puts fracking wells in our neighborhoods, threatening our lives and our children’s lives, then don’t we have a moral responsibility to blow up wells and eliminate fracking and workers?'” the lawmakers wrote. “While we are strong advocates for the First Amendment, violence toward individuals and destruction of property are both illegal and potentially fatal.”

The lawmakers also noted attempts to “shut down lines by turning valves at pump stations…Even though some activists commit these acts of sabotage to raise awareness about climate change, they only create the serious risk of harm to the environment they claim to care about.”

Asking Sessions to detail the Department of Justice’s (DOJ) efforts to prosecute recent cases involving criminal actions taken against pipelines, the lawmakers questioned whether “the attacks against the nation’s energy infrastructure, which pose a threat to human life, and appear to be intended to intimidate and coerce policy changes, fall within” the DOJ’s definition of domestic terrorism.

“Environmental activists who choose to use violence against our nation’s energy infrastructure and the men and women who work in the energy industry should be prosecuted to the full extent of the law,” Buck said of the letter to Sessions. “While I will continue to support their right to protest policies they disagree with, we need to send a strong message to those who destroy property that such dangerous behavior will not be tolerated by the communities who live around and rely on this energy infrastructure.”

The American Petroleum Institute (API) praised the lawmakers for urging Sessions to take action against pipeline saboteurs.

“Safety is our industry’s core value, and any illegal or dangerous effort to undermine safety and bring harm to the environment and communities should be prosecuted to the fullest extent of the law,” API Midstream and Industry Operations Group Director Robin Rorick said. “We take these attacks very seriously, and we welcome the bipartisan efforts in Congress to strengthen our nation’s infrastructure that delivers the energy Americans demand every day.”

API has been working with the Trump administration on this issue, including the DOJ, the Federal Bureau of Investigation and the Pipeline and Hazardous Materials Safety Administration, among others, the group said.

“A key component of securing our nation’s energy infrastructure is ensuring that law enforcement has the tools needed to prosecute those who attack it,” Rorick said.

In recent years, pipeline operators have dealt with heightened opposition to new projects, fed by anti-fossil fuel activism. Many projects have faced fierce opposition during the regulatory process, and protests and demonstrations against Energy Transfer Partners LP’s Dakota Access Pipeline (DAPL) grew heated, grabbing national headlines last year.

In August, Energy Transfer filed a complaint in federal court calling the DAPL protest organizers “a network of putative not-for-profits and rogue eco-terrorist groups,” accusing them of carrying out cyberattacks against Energy Transfer and its employees, inciting violence during protests against the crude oil pipeline and engaging in a campaign to harm the company’s financial standing.