Amazon said Thursday it will protest a Pentagon decision to award Microsoft a massive cloud computing contract worth up to $10 billion, citing “unmistakable bias” and “political influence.”

The controversial and long-delayed Joint Enterprise Defense Infrastructure contract had been widely expected to go to Amazon Web Services but was instead awarded to rival Microsoft last month. Amazon spokesman Drew Herdener said in an e-mailed statement that contract awards should be “free from political influence.”

In July, President Trump directed Defense Secretary Mark T. Esper to reexamine the contract, citing concerns it would go to Amazon.

(Amazon CEO Jeff Bezos owns The Washington Post.)

In an emailed response to Amazon’s statement Defense Department spokeswoman Elissa Smith said “we will not speculate on potential litigation.”

The JEDI contract, announced in March 2018, is meant to modernize the Pentagon’s computing infrastructure in the hands of a commercial tech company.

“AWS is uniquely experienced and qualified to provide the critical technology the U.S. military needs, and remains committed to supporting the DoD’s modernization efforts,” Herdener said. “We also believe 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. 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.”

Amazon is the commercial cloud computing market leader by a long-shot, holding a leading 48 percent market share, according to market-research firm Gartner. Microsoft is the second-largest with a 15.5 percent share.

Amazon is also the only company to hold the Defense Department’s highest-level security certification, called Impact Level 6. Microsoft made important strides during the year-long period the award was tied up in litigation, finalizing a number of partnerships that observers say may have narrowed the field somewhat.