Updated 1/27/2017 at 7:24 PM EST with the text of the executive order.

WASHINGTON – President Donald Trump on Friday signed an executive order that will lead to what he called "a great rebuilding" of the military.

The directive, signed during the commander in chief's first visit to the Pentagon, calls for reviews of readiness capabilites, as well as formal looks at the nuclear and missile defense portfolios now in the hands of Defense Secretary Jim Mattis, who was officially sworn into office by Vice President Mike Pence during the visit. 

During a brief speech, Trump described the American military as "the greatest force for justice and peace and goodness that have ever walked the face of this earth. Your legacy exists everywhere in the world today where people are more free, more prosperous, and more secure because of the United States of America."

As a result, Trump said signing what he called an "executive action" would lead to "developing a plan for new planes, new ships, new resources and new tools for our men and women in uniform, and I'm very proud to be doing that.

"As we prepare our budget request of Congress, and I think Congress is going to be very happy to see it, our military strength will be questioned by no one, but neither will our dedication to peace. And we do want peace," he added.

A draft of the order was published online Thursday by the Washington Post. As part of that draft order, the Pentagon was directed to conduct a 30-day review of the US-led effort to defeat the Islamic State group, and to evaluate how prepared the American military is to deal with near-peer competitors like Russia and China. It also instructed the Pentagon and the Office of Management and Budget (OMB) to develop — within 90 days — an emergency budget amendment to boost military spending this year, and for Mattis to update and revise existing budget plans for fiscal year 2018, the Post reported. Finally, the draft requested Mattis develop a new national security plan by next January, which would include plans for modernizing the nuclear forces and developing new missile defense capabilities.

However, the final version of the language, released late Friday, varies from the draft version.

In the actual signed version, the focus is on improving readiness long term. The language ordering updates to the FY18 budget on a timetable are no longer there, instead replaced with a broader order to "develop levels" for 2018 in conjunction with OMB. The report now orders a full-up Nuclear Posture Review and a Ballistic Missile Defense Review, which will be led by the department.

Perhaps most notably, the final language does not include any mention of the Pentagon drafting a nationals security plan, instead directing the secretary to develop a National Defense Strategy "upon transmission of a new National Security Strategy to Congress." Loren DeJonge Schulman, a former official at the National Security Council and the Pentagon, now with the Center for a New American Security, said that language was a particularly odd aspect of the draft.

"While a new administration giving written guidance to the Department of Defense on its strategy and budget isn't unprecedented, the draft EO is both strange and problematic," Schulman said earlier in the day. "It's a major case of putting the cart before the horse. Telling the department where and how to invest before the administration conducts any review of its strategy isn't just bad process, it's bad for the military.

"Written commander's intent is nothing new at DoD, but giving this text force of law for the executive branch is overkill - the content of the EO could just as easily be conveyed to Mattis as marching orders. But an EO gives it a public (and press) component since they have to be published on the federal register," Schulman noted.

More specifically, Schulman raised questions about the order for the Pentagon to develop a national strategy rather than the NSC.

"Buried in the text is a huge issue: tasking DoD to develop a national security strategy," she said. "The National Security Strategy is a report transmitted by the president to Congress and normally drafted by the president's national security staff.  Assigning the pen to the Pentagon is unprecedented and bizarre."

That issue now appears to be a non-issue, although other questions have now arisen. In particular, iIt is unclear at the moment exactly how much the executive order can do about the budget — a view the House Armed Services Committees Democrats made clear in a tweet during the event, when it sent out a note that "Fun fact: Under Article 1, Section 8 of the Constitution, Congress has the exclusive power to rebuild the military."

Another potential challenge with the order is the expected clash between what the Pentagon wants and the views of Trump’s nominee to head OMB, Rep. Mick Mulvaney, R-S.C.. Mulvaney strict budget hawk who is widely expected to refuse budget increases unless they are balanced out with cost cuts from elsewhere in the government, and defense analysts generally agree that for Trump to reach the heights of military spending he seeks, he will have to increase the defense budget significantly, something that could be a challenge under Mulvaney’s strict guidelines.

Todd Harrison, a budget analyst with the Center for Strategic and International Studies, also notes that pushing out any sort of budget move out of OMB in the near term may be difficult, as Mulvaney’s views are likely to clash with those of the professional staff who have been there a while — requiring Mulvaney and his team to go back and redo much of the preliminary work that has been laid down already.

Before signing the executive order on Friday, Trump convened an hourlong meeting with Mattis, the Joint Chiefs of Staff and Air Force Gen. Joseph Lengyel, who runs the National Guard Bureau. They were joined by Pence and the president's national security adviser, retired Lt. Gen. Mike Flynn, a defense official said.

The meeting was run by Trump and focused predominantly on his desire to "accelerate the defeat of ISIS," the official said. The president set no deadlines, however, and "the chiefs did most of the talking," the official added. The discussion, he said, was "very cordial."

"I think everyone's in agreement that we want to defeat ISIS quickly," the official said.

The leaders also discussed the president's focus on rebuilding the military and improving its ability to respond to contingencies. 

At the meeting's outset, Trump as provided with a briefing on the military's geographic combatant commands, which oversee US military operations throughout specific parts of the world, the official said. "And then there was an interesting discussion on the role of the National Guard, and how they work for state governors."

The full text of the executive order is as follows:

By the authority vested in me as President by the Constitution and the laws of the United States, including my authority as Commander in Chief of the Armed Forces of the United States, I hereby direct the following:

Section 1. Policy. To pursue peace through strength, it shall be the policy of the United States to rebuild the
U.S. Armed Forces.

Sec. 2. Readiness.
(a) The Secretary of Defense (Secretary) shall conduct a 30-day Readiness Review. As part of this review, the Secretary shall:
(i) assess readiness conditions, including training, equipment maintenance, munitions, modernization, and infrastructure; and
(ii) submit to the President a report identifying actions that can be implemented within the current fiscal year and that are necessary to improve
readiness conditions.
(b) Concurrently with the Readiness Review, the Secretary, together with the Director of the Office of Management and Budget (OMB), shall develop a Fiscal Year (FY) 2017 budget amendment for military readiness, including any proposed reallocations.
(c) The Secretary shall work with the Director of OMB to develop levels for the Department of Defense's FY 2018 budget request that are necessary to improve readiness conditions and address risks to national security.
(d) Within 60 days of the date of this order, the Secretary shall submit to the President a plan of action to achieve the levels of readiness identified in the Secretary's Readiness Review before FY 2019. That plan of action shall address areas for improvement, including insufficient maintenance, delays in acquiring parts, access to training ranges, combatant command operational demands, funding needed for consumables (e.g., fuel, ammunition), manpower shortfalls, depot maintenance capacity, and time needed to plan, coordinate, and execute readiness and training activities.

Sec. 3. Rebuilding the U.S. Armed Forces.
(a) Upon transmission of a new National Security Strategy to Congress, the Secretary shall produce a National Defense Strategy (NDS). The goal of the NDS shall be to give the President and the Secretary maximum strategic flexibility and to determine the force structure necessary to meet requirements.
(b) The Secretary shall initiate a new Nuclear Posture Review to ensure that the United States nuclear deterrent is modern, robust, flexible, resilient, ready, and appropriately tailored to deter 21st-century threats and reassure our allies.
(c) The Secretary shall initiate a new Ballistic Missile Defense Review to identify ways of strengthening missile-defense capabilities, rebalancing homeland and theater defense priorities, and highlighting priority funding areas.

With reporting by Andrew deGrandpre of Military Times.

Aaron Mehta was deputy editor and senior Pentagon correspondent for Defense News, covering policy, strategy and acquisition at the highest levels of the Defense Department and its international partners.

More In Pentagon