Two activists were arrested Monday during a protest at the Galleria-area offices of the TransCanada Corporation, whose Keystone XL pipeline is currently under construction to bring controversial tar sands to the Gulf Coast oil industry.

The Tar Sands Blockade — a non-violent coalition of climate change organizers and Texas-Oklahoma landowners — kicked off events at 10 a.m. by flooding the building's lobby with about 100 protestors, according to the group's spokesperson Ron Seifert.

"There was a lot of political theater this morning," he told CultureMap Monday afternoon. "Tar sands are the dirtiest hydrocarbon on the planet and we want to send a clear message to TransCanada that they'll be held accountable for anyone harmed by this pipeline."

After taking over the ground floor public space, the group marched around the building for several hours with the organization's Pipeline Dragon, which Seifert described as a large paper-mache creature standing in for Keystone's effects on communities and the environment. "In the end," he added, "the dragon's slain by several Tar Sands Blockaders."

The two protestors were arrested during a scheduled "Death by Tar Sands" skit, which Seifert said involved activists locking themselves to an office door and pretending they were killed by TransCanada crude.

According to the Houston Chronicle Fuel Fix blog, dozens of Houston police officers patrolled the scene on horseback as protestors passed out hand-written fliers and chanted “Toxic tar sands spill! Tar and benzene kill!”

TransCanada spokesperson David Dodson told CultureMap the protests mainly disrupted building operations for only 15 to 20 minutes, adding that most of the workers effected by the events were not even associated with the Calgary-based company or the pipeline.

“This is another example of the protestors’ attempt to stop a project that is currently providing thousands of jobs to American workers,” Dobson explained in a subsequent statement. "TransCanada has secured every permit needed to build the Gulf Coast Project. We have followed the law to the letter. We are building the safest pipeline ever built, one that will greatly enhance America's energy security."

The Monday incidents come less than a week after Tar Sands Blockaders camped out on treetop platforms to halt Keystone construction in Diboll, 100 northeast of Houston. The group arranged another tree campsite in November closer to the Dallas area.

Also on Monday, according to Ron Seifert, two members of the organization officially ended their 40-day hunger strike on behalf of citizens affected by toxins from a Houston Valero refinery expected to receive tar sands when the Keystone XL is complete.