The National Security Agency, or NSA, has been allowed to temporarily resume the mass interception and collection of telephone records, according to Reuters.
Following the high profile revelations made by Edward Snowden, an appeals court ruled that the US Patriot Act did not allow government agencies to collect data in bulk.
President Barack Obama replaced the Patriot Act with the Freedom Act earlier this year, enabling the surveillance programme to continue in its existing form for six months. However, it is only now that it has been approved by the Foreign Intelligence Surveillance Court.
"In passing the USA Freedom Act, Congress clearly intended to end bulk data collection. But what it took away with one hand, it gave back - for a limited time - with another," explained Michael Mosman, a judge for the surveillance court.
Mr Mosman also disagreed with an earlier court ruling which had claimed that the Patriot Act did not allow bulk collection of US phone records.
Wyn Hornbuckle, a spokesperson for the Justice Department agreed with the court and welcomed the decision to legitimise the existing collection programme in the transition period before a new method of collection is authorised.
The crucial difference between the Patriot Act and the Freedom Act is that although the latter still requires network operators to store user data, specifically metadata, companies only have to share this with the US government when requested to do so. Previously, this information was routinely shared en masse.