FILE PHOTO: An aerial view of the Pentagon building in Washington, June 15, 2005. REUTERS/Jason Reed/File Photo

WASHINGTON (Reuters) - The U.S. Department of Defense on Monday updated its request for proposals from potential bidders on a $10 billion project for cloud computing services, in a deal that has been closely watched because Amazon.com Inc AMZN.O has been considered to be a top contender.

Earlier this month, President Donald Trump said he would take a serious look at policies to address what he says are the unfair business advantages of online retailer Amazon, which has been interpreted as a threat to Amazon winning the cloud deal.

The competition has attracted criticism from companies that fear Amazon Web Services, Amazon’s cloud unit, will win the contract, snuffing out hopes that others will break into government cloud computing. Amazon Web Services is the only company the U.S. government has approved to handle secret and top secret data.

The Defense Department’s under secretary of defense for acquisition and sustainment, Ellen Lord, told reporters in her Pentagon office on Friday morning that at least 50 companies were competing for the contract.

Proposals from industry, according to a letter from the Pentagon to potential bidders, are needed to help the Defense Department with its broad modernization effort that will move data off older data storage facilities and into cloud computing, which is commonly used by businesses.

The selection process for the $10 billion a year contract was set for completion in September.

Several other U.S. companies including Microsoft Corp MSFT.O, Oracle Corp ORCL.N, Alphabet Inc's GOOGL.O Google are expected to compete for the two-year contract.