Talks over whether the whistleblower who sparked an impeachment inquiry into US President Donald Trump will testify to Congressional committees are hung up on the question of whether the person can submit written testimony, two sources familiar with the discussions said.
Negotiators in the Democratic-led US House of Representatives are open to the career intelligence officer making written testimony while negotiators in the Republican-majority Senate have resisted, said the sources.
The whistleblower's representatives want to make sure the person remains anonymous. Discussions between Congressional investigators and representatives of the whistleblower have been suspended at least temporarily, though the sources indicated they were expected to resume when lawmakers return from a recess next week.
Representatives of the committees had no immediate comment.