CNN — Twitter said Tuesday it will permit public institutions such as transit agencies and the National Weather Service to post large volumes of automated tweets for free, provided that the accounts doing so are “verified gov or publicly owned services.” The announcement marks another sudden pivot in Twitter’s attempts to charge institutional users for access to its platform — reflecting an apparent concession to those who warned that Twitter’s paywall plan would disrupt consumers’ ability to receive timely updates from first responders, weather agencies and other vital services for which Twitter has become an essential distribution channel. Last week, New York’s Metropolitan Transit Authority announced it would stop posting real-time transit alerts on Twitter, citing reliability issues with Twitter’s platform and saying it does not pay tech platforms for the ability to provide the updates. weeks, multiple regional accounts run by the National Weather Service have also warned followers to expect fewer weather updates in connection with Twitter’s platform changes. Tuesday’s shift comes amid a widespread backlash to Twitter’s paid plans, which cost as much as $2.5 million per year for top -level access privileges allowing organizations to download and post large volumes of tweets in an automated fashion. The changes, which took effect in March, restricted third parties from easily accessing Twitter’s application programming interface, or the technology that allows outside software to plug into Twitter’s platform. The changes provoked especially strong opposition from third-party app developers whose projects depend on uninterrupted Twitter access, as well as from academic researchers that study platform manipulation and misinformation, who said even the most expensive new plans provided just a fraction of the data Twitter once offered at no or low cost. On Tuesday, Twitter’s official account for developers acknowledged the impact the company’s paywall could have on civil society. “One of the most important use cases for the Twitter API has always been public utility,” it said “Verify Gov or Publicly Owned Services Who Tweet Weather Alerts, Transport Updates and Emergency Notifications May Use the API, for the Critical Purpos ES, for free. “But While Twitter Appeared to Be Backing Off FROM An Attempt to Charge Vital Services Substantial Fees Fors fors API access, the announcement left it ambiguous regarding how Twitter planned to ensure that critical public safety and transit accounts would be “verified.” Requiring that the accounts be verified under Twitter’s paid subscription program, Twitter Blue, could still involve forcing institutions to pay to access Twitter’s API. Twitter’s developer account didn’t immediately respond to CNN’s questions seeking clarification on the matter.