Husain Haqqani told Pakistan's Geo News U.S. authorities are currently investigating email and telephone threats he received concerning the Memogate case.
Haqqani has been implicated in a scandal involving a memo delivered to a top U.S. military official that offered greater cooperation with the United States in the aftermath of the 2011 raid that killed Osama bin Laden.
On Tuesday Pakistan's Supreme Court ordered the country's interior secretary to finalize security arrangements so Haqqani could return and testify, The Express Tribune reported.
Chief Justice Iftikhar Muhammad Chaudhry also asked the interior secretary to talk to Haqqani regarding his security concerns.
Haqqani, who has not been charged with a crime, said he is "a very likely target of hyper-nationalist vigilantes of which many are currently active all over Pakistan including within the security services."