The contract would fund a cloud computing deal known as JEDI. Earlier this week, Amazon Web Services said it was seeking to depose President Trump and Defense Secretary Esper to provide testimony in the case.
Amazon won a court order on Thursday temporarily blocking a $10 billion (€9.2 billion) US military contract with Microsoft.
A US judge granted the company's request for a preliminary injunction to pause the contract, which would fund a multi-billion-dollar cloud computing deal known as the Joint Enterprise Defense Infrastructure, or JEDI.
Both the documents requesting the block and the judge's decision to issue the injunction were sealed by the court.
Judge Patricia E. Campbell-Smith also released a sealed opinion accompanying the decision and ordered Amazon to post $42 million to cover damages in the event that the injunction was issued wrongfully.
Microsoft said in a statement on Thursday that it was disappointed by the additional delay, but added that it believed it would ultimately be allowed to carry out the project. Amazon was initially favored to win the contract, which defense officials say will advance the US military's technological advantage.
The JEDI project would store and process classified data, allowing the military to boost communication with soldiers on the battlefield and use artificial intelligence to speed up its war planning and fighting capabilities.
A Trump-Bezos business saga
Earlier this week, Amazon Web Services said it was seeking to compel US President Donald Trump and Defense Secretary Mark Esper, among others, to provide testimony in the lawsuit.
In July, Trump publicly stated that the contract "wasn't competitively bid," and he said the administration would "take a very long look" at it. In August 2019, weeks before the winner of the contract was set to be announced, Trump ordered the contract placed on hold for Esper to investigate possible favoritism towards Amazon. In October 2019, Microsoft was announced as the winner of the contract.
Trump has repeatedly attacked Amazon CEO Jeff Bezos, taking aim at the company's tax breaks and ownership of the Washington Post newspaper, which is often critical of the US president.