(Bloomberg) -- Amazon.com Inc. filed a lawsuit on Friday challenging the Defense Department’s choice of rival Microsoft Corp. for a Pentagon cloud-computing contract worth as much as $10 billion.

The lawsuit, which was filed under seal in the U.S. Court of Federal Claims in Washington, marks Amazon’s most aggressive push to defend its competitive edge in the lucrative and cutthroat world of federal government contracts.

Amazon previously said it planned to formally protest its loss of the Pentagon’s Joint Enterprise Defense Infrastructure, or JEDI, cloud contract because the evaluation process was deficient.

“It’s critical for our country that the government and its elected leaders administer procurements objectively and in a manner that is free from political influence,” Amazon spokesman Drew Herdener said in a Nov. 14 statement. “Numerous aspects of the JEDI evaluation process contained clear deficiencies, errors, and unmistakable bias -- and it’s important that these matters be examined and rectified.”

Elissa Smith, a spokeswoman for the Defense Department, said in a statement that it, along with the Justice Department, would review the lawsuit. She added that the Pentagon “was confident in the JEDI award. The source selection process was conducted in accordance with the stated criteria in the solicitation and procurement law.”

Representatives of Amazon didn’t immediately respond to requests for comment on Friday night.

Read More: Amazon Seen Focusing on Trump in Pentagon Contract Challenge

In court paperwork, Amazon said the lawsuit was filed under seal because it contains “sensitive” information that “would cause severe competitive harm” if it’s released.

Political Influence

Microsoft asked to intervene in the suit, arguing in a filing that the case will “directly affect Microsoft’s interests” and “carries the potential for significant economic and other harms to Microsoft.”

It’s widely expected that Amazon will argue that its loss of the high-profile contract was due to improper political influence by President Donald Trump. Exhibits filed with Friday’s complaint include Trump’s comments to the press in July as well as a Fox News segment called “Swamp Watch.”

In July, Trump stunned lawmakers and technology companies when he openly questioned whether the JEDI contract was being competitively bid, citing complaints from Microsoft, Oracle Corp. and International Business Machines Corp. Trump has long criticized Amazon founder Jeff Bezos on everything from the shipping rates his company pays the U.S. Postal Service to his personal ownership of what Trump calls “the Amazon Washington Post.”