Nearly an hour after Governor Gregg Abbott signed Senate Bill 4 into law, protesters gathered outside of the Governor's mansion to denounce it.

Abbott signed the legislation, which bans so-called 'sanctuary cities' in the state of Texas, during an impromptu Facebook Live video Sunday night.

RELATED: Gov. Abbott signs so-called 'sanctuary city bill' into law on Facebook Live

Austin City Council Member, Gregorio Casar, who was arrested last week after a sit-in, tweeted, "@GovAbbott signed the racist #SB4 tonight. The community is outside his mansion right now-- we will NOT let him win."

PHOTOS: Protesters against 'sanctuary city law' flock to Governor's mansion

Austin Mayor Steve Adler released the following statement on SB 4 becoming law:

“Our law enforcement community could not have been clearer with the legislature: By driving people into hiding, this bill will make it harder to catch criminals, but this bill has never really been about keeping our cities safe.”

Follow along with the growing discussion below: