Gen. Keith Alexander, director of the National Security Agency, convened an emergency, "top secret" meeting Tuesday with House members to dissuade them from voting for Rep. Justin Amash's NSA amendment, according to an invitation obtained by the Huffington Post.

Alexander met first with House Republicans and then with House Democrats, according to Fox News.

There is concern that the Michigan Republican's amendment, which would prohibit the NSA from collecting phone records and other data about individuals not under investigation or risk losing funding, could expose certain ultra-sensitive NSA programs. After leaving the meeting with Alexander, Amash said "they're making progress" in drumming up support for his amendment.

Neither Alexander nor Amash responded to requests for comment.