Boston Police took three protestors into custody Tuesday morning at the site of the expansion of a natural gas pipeline in West Roxbury.

The demonstrators planned to block construction of the line, an extension of the Algonquin Gas Transmission pipe operated by Texas’ Spectra Energy Corp.

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The trio were among a couple dozen demonstrators there, most of whom stood on the sidewalk near a construction site. The three taken into custody around 10:15 a.m. had been standing inside the site.

It was the latest in a series of protests related to the pipe, which opponents have said would ratchet up dependence on natural gas, rather than renewable sources of energy like wind and solar, and would pose the risk of leaks.

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The pipeline had also inspired lawsuits against the company, and opposition to its construction included support from many public officials, among them city councilors and Boston Mayor Marty Walsh.

A police spokesman said he couldn’t comment yet on whether the protestors would face charges because the investigation was ongoing.