(CNN) -- The government of Brazil has filed a lawsuit against Twitter, demanding the micro-blogging site suspend the accounts of users who tip drivers off to police roadblocks and radar traps.
The move comes less than two weeks after Twitter said it would begin deleting users' tweets in countries that require it, and may be the first time a government has taken the site up on its offer.
The suit, filed Monday in a federal court in Goias by the attorney general's office, also targets users who blow the cover of police lying in wait. The government is seeking fines of 500,000 reais ($290,000) for each day that Twitter or traffic whistle-blowers fail to comply.
"It looks like Twitter built it, and they came," said Eva Galperin, an activist with the Electronic Frontier Foundation, which defends free speech and privacy online.
As far as she knows, the Brazil case represents the first time a government has sought to make Twitter delete content since the company announced it would do so in countries that require it.
The government based its suit on the contention that by alerting drivers to the time and place of roadblocks, Twitter and its users are breaking the law and "directly endangering life, safety and property."
Attorneys argued that besides reducing the number of traffic accidents, checkpoints set up by transit police "serve to combat other serious crimes, such as car theft, the transport of illegal weapons and drug trafficking," according to a statement from the attorney general's office.
They cited various studies to show the toll of traffic accidents, saying that 55,000 people die each year on the country's sprawling highways and that accidents cost Brazil 24.6 billion reais ($14.25 billion) in damage, health care costs and lost productivity.
A judge must now decide whether to back the request. No one at Twitter was immediately available to comment on the case.
The lawsuit had an immediate chilling effect on users who post about the country's often congested traffic conditions.
Before news of the suit spread, @RadarBlitzGO in Goiania, the state capital of Goias, was buzzing with information from drivers about traffic jams and blockages, with tip-offs about police activity.
Monday afternoon, though, the site posted a succinct tweet to its roughly 12,000 followers: "It's the end."
"We haven't received any guidance from Twitter. But we're shutting down of our own accord," it wrote. "In light of the civil action proposed ... we are suspending updating until the court rules."
The site has since been idle.
"It certainly lets Brazilians know that the government is willing to make these requests of Twitter. It remains to be seen whether Twitter is going to comply with them," said Galperin.
Late last month, the company said it would begin deleting users' tweets in countries that require it, but keep those deleted tweets visible to the rest of the world.
The move was significant because, previously, the only way the company could comply with countries' limits was to remove the content globally.
"One of our core values as a company is to defend and respect each user's voice," Twitter wrote in a blog entry then. "We try to keep content up wherever and whenever we can, and we will be transparent with users when we can't. The tweets must continue to flow."