Apple saw a spike in government requests for data relating to national security in the second half of 2016, according to a report released by the technology giant.

In the six months ended December 2016, the Cupertino-based firm received 5,999 government requests. This was up from the 2,999 it got in the first half of 2016. Such requests are orders received under the Foreign Intelligence Surveillance Act or requested in a National Security Letter (NSL).

The Federal Bureau of Investigation (FBI) or National Security Agency (NSA) could request such data from Apple. Apple said that the requests had affected 4,999 accounts.

It also revealed the presence of a declassified NSL. These letters are usually classified and do not allow the company to disclose the contents even to the customer concerned. But under recently introduced laws, the FBI regularly reviews such gag orders and declassifies some letters. Companies like Google have made some of its NSL public. Apple so far has not chosen to disclose the content of its letters.