( CNN ) -- Transit officials in San Francisco reopened all downtown subway stations Monday evening after successively opening and closing them to stem the threat of spreading protests . `` All BART Stations are Now Open , Trains Running On Time , '' said a release from Bay Area Rapid Transit . The situation was fluid most of the evening , with officials trying to thwart demonstrators , closing and reopening the Civic Center and Montgomery stations , closing the Powell station , then at least partially reopening Powell to allow riders to disembark . Police officers in response gear stood at the Civic Center station , with one officer on a megaphone telling people , `` This is your final warning , the station is closed . '' On the streets , small groups of protesters could be seen gathering to criticize BART after several shootings involving its police officers -- the latest coming last month and resulting in the death of 45-year-old Charles Hill . Meanwhile , an official with the system stood by the decision to shut off cell phone service ahead of a protest last week . The decision Thursday to `` temporarily interrupt ... service at select BART stations as one of many tactics to ensure the safety of everyone on the platform '' drew widespread criticism and stirred the well-known hacking group Anonymous to stage an `` operation '' Sunday . The group urged those supporting its cause to attend a `` peaceful protest '' at 5 p.m. Monday at the system 's Civic Center stop . `` What we 're going to do is take the appropriate steps within the Constitution , '' he said . `` There are more constitutional rights than just free speech . There is the right to be safe . '' Last week 's protest never materialized . But the decision to cut cell service elicited fresh condemnations from civil liberty organizations , the San Francisco Chronicle 's editorial page and others . `` All over the world people are using mobile devices to organize protests against repressive regimes , and we rightly criticize governments that respond by shutting down cell service , calling their actions anti-democratic and a violation of the rights to free expression and assembly , '' Rebecca Farmer from the ACLU 's northern California office wrote on the advocacy group 's website . `` Are we really willing to tolerate the same silencing of protest here in the United States ? '' Online messages attributed to Anonymous took credit for the apparent hacking Sunday of myBART.org , a link off BART 's website that showed a page featuring , among other items , the hacking group 's logo -- a smirking mask above two crossed swords , all on a black background . In addition , Twitter traffic related to Anonymous boasted that hackers had been able to get into BART 's internal network . Several related items and documents were posted , including one claiming to be `` the User Info Database of MyBart.gov . '' This had e-mails and , in some cases , phone numbers and addresses of hundreds of people . `` By ( cutting cell service ) , you have not only threatened your citizens ' safety , you have also performed an act of censorship , '' a seemingly computer-generated voice -- speaking over dramatic music and images -- said in a video posted online Sunday afternoon . `` By doing this , you have angered Anonymous . '' The Federal Communications Commission is collecting information on the matter , with agency spokesman Neil Grace saying Monday by e-mail that `` any time communications services are interrupted , we seek to assess the situation . '' `` We ... will be taking steps to hear from stakeholders about the important issues those actions raised , including protecting public safety and ensuring the availability of communications networks , '' said Grace . Yet on Monday , Johnson emphatically stood by BART 's move , made on the same day British Prime Minister David Cameron proposed a crackdown on social media to quell riots . `` We made a gut-wrenching decision that was forced upon us by the protesters , '' Johnson said . `` They made us choose between people 's ability to use their mobile phones ( and ) their constitutional right to get from point A to point B . '' CNN 's Greg Botelho contributed to this report .
NEW : Trains are now running normally , BART says . A BART official says the system was `` forced '' to act to protect passengers ' safety . Citing `` important issues , '' a spokesman says the FCC is probing cutting cell service . The Bay Area Rapid Transit system 's action last week drew criticism , stirred an online attack .