( CNN ) -- The fight to block construction of the Keystone XL tar sands pipeline through east Texas stepped up Monday as protesters locked themselves to machinery . Dozens of others formed a human chain to keep heavy machinery from moving around the proposed pipeline 's path in Cherokee County , said Ethan Nuss , spokesman for the Tar Sands Blockade group . Three protesters at another location suspended themselves from 50-foot pine trees with their life lines anchored by the construction equipment , Nuss said . Cherokee County sheriff 's deputies used `` pain compliance '' measures , including pepper spray , to remove the four protesters locked to the machinery , Nuss said . The four were dragged away `` very aggressively and painfully '' and arrested , he said . Protesters , police clash in Cairo . Two others were arrested when they tried to block a cherry picker crane to remove the protesters from the trees , Nuss said . A 75-year-old woman was among those pepper sprayed and arrested , he said . `` Some peaceful protesters doing nothing more than holding signs by the road were violently pepper sprayed , '' said group spokesman Ron Seifert . Demonstrators demand Obama reject pipeline . All of the blockade protesters were removed from the construction sites by 2 p.m. and 12 of them were arrested , he said . Meanwhile , a sheriff 's spokesman confirmed six arrests , but provided no other details . TransCanada , the company building the pipeline , did not immediately respond to CNN calls for comment Monday . `` Today 's Day of Action is in solidarity with local landowners struggling to protect their water and land from TransCanada 's toxic tar sands pipeline , '' the protest group said in a written statement Monday . Jordanians protest high gas prices . While construction of some segments of the proposed 1,700-mile pipeline has not been approved , the Texas government and courts have cleared its path through that state . If completed , it would transport tar sands mined in Canada to refineries on the U.S. Gulf Coast . Opponents want U.S. President Barack Obama , who in the past has rejected rapid approval , to outright reject the pipeline project , arguing it would be an environmental disaster . Actress Daryl Hannah was arrested last month in Wood County , Texas , when she and another woman tried to stop a bulldozer from clearing land along the pipeline path . Bill McKidden , founder of 350.org , said a demonstration in Washington on Sunday was to remind the Obama administration of its commitment to preventing fossil fuel based projects that they say are causing increased climate change . `` They said a year ago they would study it further , now that year is up , and in the meantime we 've had the hottest year in America history , we 've had an epic drought , we 've had the Arctic melting and we 've had Superstorm Sandy flooding the subways of New York , '' said McKibben . `` The pipeline has come to symbolize something much , much bigger than just one energy project , it 's come to symbolize what is our energy future , and what President Obama is going to do on climate change , '' said activist Jane Kleeb of the anti-pipeline organization Bold Nebraska , in a state where the Keystone XL project would cut through predominantly agricultural areas . CNN 's Nick Valencia contributed to this report .
Dozens formed a ` ` human barrier '' to keep heavy machinery from working at pipeline site . Three protesters suspended themselves from two pine poles to stop pipeline work . Deputies used pepper spray to remove protesters , group says . Company building the pipeline did not immediately respond to the protests .