The British government has complained to Twitter over a block on access to data from the social network, which it was reportedly using to track potential terror attacks, officials said Wednesday.
"The government has protested against this decision and is in ongoing discussions with Twitter to attempt to get access to this data," a Home Office spokesman said.
Prime Minister Theresa May's spokesman declined to specify exactly what the data was and why it was important, saying only that "we wish to have access to this information".
But he told reporters: "The fight against terrorism is not just one for the police and the security services. Social media and tech companies have a role to play."
The Daily Telegraph newspaper reported that the government had been tracking terms related to potential terror attacks via a third-party firm, but this had now been blocked.
In a blog posting in November, Twitter executive Chris Moody said the firm encouraged developers to create products that used real-time data from the social network "in the public interest", for example tracking emergencies and natural disasters.
"Recent reports about Twitter data being used for surveillance, however, have caused us great concern," he wrote.
He said that tracking or profiling protesters or activists was "absolutely unacceptable and prohibited", including via Twitter's application software programmes.
"We prohibit developers using the Public APIs and Gnip data products from allowing law enforcement - or any other entity - to use Twitter data for surveillance purposes. Period," he said.