Greenpeace activists were hanging by bungie cords from the Fred Hartman Bridge in Houston in an effort to bring awareness to climate change by blocking the Houston Ship Channel. The protest, which comes hours before a Democratic presidential debate, led to the closure of part of the channel, the Coast Guard said.

"We're in Houston shutting down the largest oil export channel in the country to resist Trump & the oil industry for fueling this #ClimateCrisis. It's time to end the age of oil. #PeopleVsOil" Greenpeace USA tweeted.

Environmental activists affiliated with the organization Greenpeace dangle off the Fred Hartman Bridge in Houston in an act of protest on Sept. 12, 2019. KHOU-TV

According to CBS affiliate KHOU-TV, 11 activists are suspended from below the bridge with flags. KHOU reports sheriff's deputies confirmed that they would not attempt to force a rescue or remove the activists unless they become a safety or health hazard, as they don't want to risk lives.

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The activists are expected to face multiple charges once they conclude their protest, including obstructing the roadway and obstructing the waterway. Harris County Sheriff Ed Gonzalez tweeted that his office "is aware of a public demonstration currently underway at the Fred Hartman bridge in East Harris County."

@HCSOTexas is aware of a public demonstration currently underway at the Fred Hartman bridge in East Harris County. We are actively monitoring the situation with other public safety partners. #HouNews pic.twitter.com/l2m1SweK0N — Ed Gonzalez (@SheriffEd_HCSO) September 12, 2019

A Greenpeace spokesperson told KHOU that the activists "have food and water, plus proper training" in order to hang suspended for an extended period of time. Greenpeace's official Twitter account has tweeted out support for the protesters, urging others to "join the action with us!"

The protest comes as the top Democratic presidential primary candidates are in Houston tonight for the third Democratic debate