Defense Secretary Jim Mattis has directed Pentagon budget planners to lay the groundwork for an ambitious rebuilding effort, one that will, in the near term, address President Trump's desire to bring more military force to bear on the Islamic State while also growing the United States' capacity to oppose "high-end competitors" such as Russia and China.

Mattis issued the directive Tuesday, distributing a memo that maps out in broad terms a number of objectives, including actions meant to address what military leaders see as immediate readiness shortfalls, and to add an unspecified number of military personnel and support structure in the months and years to come. The overarching priority, according to Mattis' memo, is to "build a larger, more capable and more lethal joint force," and that will come by way of a new national defense strategy, the memo says.

READ THE MEMO: Mattis' budget directive

First, the Pentagon will prepare a budget request for the remainder of 2017. That's due to Deputy Defense Secretary Bob Work by March 1, the memo says.

After Trump's election, in a move anticipating his desire to rethink military spending at large, Congress approved a defense spending plan only through the winter. Mattis' effort will focus on infusing cash where it's needed to speed the Islamic State campaign, and on enabling the military to keep up — or even step up — its presence in other parts of the world where the U.S. has pressing strategic interests. That's likely to include regions such as Eastern Europe, the South China Sea and several unstable pockets throughout Africa.

Trump signs executive order promising a ‘great rebuilding’ of the military

By May, the Pentagon will have its 2018 budget request complete. There, Mattis wants to focus on buying weapons whose stocks have been depleted, addressing acquisition programs that are behind schedule, growing overall military force structure and fixing important facilities that need upgrades or have fallen into disrepair.

The new fiscal year begins Oct. 1.

Mattis' broader defense strategy overhaul will target years 2019 through 2023, the memo says. This effort calls for a new force size and enhancing the U.S. military's "lethality" — not only against its peers in Russia and China but against a "broad spectrum of threats," a reference that's likely to include the less sophisticated terror groups.

Mattis wants to "grow the force quickly, but responsibly," his memo says.

On Capitol Hill, lawmakers say appropriating and policy-making for defense will be complicated this year because Congress failed to pass a defense appropriations bill last year, and because of the Trump administration's timing. The annual National Defense Authorization Act, which the House and Senate armed services committees typically mark up at the end of April, may come later than usual, House Armed Services Chairman Rep. Mac Thornberry, R-Texas, said Wednesday.

"The problem is we have to finish '17, deal with '18 before you get to the supplemental" budget request, Thornberry said. "So Congress not doing our job, not finishing '17 before the end of the year, has had a consequence."

Andrew deGrandpre is Military Times senior editor and Pentagon bureau chief. On Twitter: @adegrandpre. With reporting by Joe Gould, who covers Congress for Defense News. On Twitter: