A previously sanctioned Russian company's investment in a Kentucky aluminum mill has been questioned in a letter published by U.S. Sen. Ron Wyden (D-Ore.) after concerns over the timing of the investment.
The snooping devices are known as 'Stingrays' and are typically purchased by law enforcement.
Bipartisan calls for Facebook to testify on Capitol Hill intensified Monday as an Oregon senator demanded that Mark Zuckerberg address alleged data abuse.
It was the second request for Trump's returns by Senate Democrats in as many weeks, part of a Democratic campaign to pressure Republicans in Congress into obtaining the documents.
The battle may determine the fate of the president's signature foreign policy achievement.