Washington (CNN) The Pentagon unveiled President Donald Trump's defense budget request Tuesday, which seeks billions in extra funds for the military -- but falls well short of what some Republican lawmakers have sought.

The total amount being requested is about $639 billion, including $574.5 billion for the base Pentagon budget and $64.6 billion for contingency operations, like the current missions in Iraq and Afghanistan.

The Trump administration is seeking an increase to the base budget of about $52.8 billion, representing a 9.8% increase over the Fiscal Year 2017 request, which adhered to the "sequestration" budget caps instituted by the Budget Control Act. The increases would largely go toward funding training, maintenance, replacing munitions, bombs and missiles, used in Iraq and Syria, and paying for thousands of additional soldiers and marines.

But the sought-after funds represent only a $19 billion, or roughly 3%, increase over what former President Barack Obama said his administration would seek for Fiscal Year 2018, causing the request to be met with fierce criticism from defense hawks on Capitol Hill, who decried the proposal as falling well short of Trump's promises of massive increases for defense.

"It's basically the Obama approach with a little bit more, but not much," Rep. Mac Thornberry, the chair of the House Armed Services Committee, said Monday at an event at the Brookings Institution in Washington, DC.

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