(CNN) The chairman of the House Armed Services Committee plans to call for a $2.1 billion boost to the US military in the Pacific region to bolster it against threats from North Korea and China.

Texas Republican Mac Thornberry will introduce a bill this week that would provide $1 billion in munitions and $1 billion for missile defense, including more interceptors for Terminal High Altitude Area Defense, or THAAD, in the Pacific, according to a summary of the legislation obtained by CNN.

The measure would also include $100 million for joint exercises with US allies in the Pacific and would require maintaining a combat aviation brigade in South Korea for responding to any military provocation from Pyongyang.

In an interview, Thornberry said his goal was "to put specific dollars" into the US military in the Pacific, "so that it's not just words, but it's capability that backs it up."

Thornberry's bill is one of several efforts underway in Congress to address shortfalls that US Pacific Command has detailed, including munitions, submarines, missile defense capabilities and manpower. The push to direct new resources to the Pacific region comes as North Korea ramps up its nuclear and missile testing -- with a stated goal of developing a long-range nuclear missile that can hit US soil. Pyongyang launched its second medium-range missile test in less than a week Sunday.

Earlier this year, Senate Armed Services Chairman John McCain introduced his own effort, called the Asia Pacific Stability Initiative, which would add $7.5 billion to the US military budget for the region over the next five years.

Defense Secretary James Mattis has expressed support for the concept, and the Pentagon will formally endorse McCain's fund in its upcoming budget, which is being released Tuesday, according to two US officials. The budget won't include a major funding contribution like McCain is seeking, according to one of the officials, but it will lay the groundwork to ramp up the funding the following year.

Lawmakers on the defense committees say the threat from North Korea has not necessarily changed in recent weeks, but Kim Jong Un's aggressive pursuit of a long-range nuclear missile has crystallized the threat for many in Congress, as well as the public.

"It makes it easier for those members who have a tendency to focus on Europe and the Middle East to remember that we have to keep our eye on" the Pacific, Hawaii Democratic Sen. Brian Schatz told CNN.

The focus on the Pacific also comes as US allies in the Pacific remain wary of the Trump administration and President Donald Trump's previous comments that he might not be committed to the security of allies in the region -- such as when he suggested South Korea should pay for the US deployment of THAAD.

Mattis has tried to foster that reassurance among Asia-Pacific allies, however, and his first trip as Defense secretary was to the Pacific.

Navy Adm. Harry Harris, head of US Pacific Command, has provided a lengthy road map for Congress to provide him more capabilities.

At recent congressional hearings, Harris said he has only half the number of attack submarines he'd like in the region, he would want more missile interceptors, including deployed to Hawaii, to guard against potential missile threats from North Korea. Harris also agreed with concerns expressed by Hawaii Sen. Mazie Hirono about manpower cuts to the Pacific Command headquarters as part of Defense Department-wide reductions.

"We all should seek efficiencies where we can, but I'm not supportive of the idea of salami slicing either," Harris said.

Pacific Command has lost more than 100 officials as part of a 20% reduction mandated by former Defense Secretary Chuck Hagel, and along with US Forces Korea will be reduced by another 50 staffers, according to Pacific Command documents provided to Congress and obtained by CNN.

The Obama administration had also called for refocusing its attention to the Asia-Pacific region -- the Pacific pivot, as it was known -- but many Republican critics say the pivot never materialized, as the military had to keep efforts focused on ISIS and the war in Afghanistan.

The Pacific push from McCain and Thornberry, who both lead the annual defense authorization bill that sets Pentagon policy, is in fact modeled after an Obama-era effort: the European Reassurance Initiative.

That was a fund that has added billions to the Pentagon budget to bolster the US military in eastern Europe following Russia's invasion of Crimea. It was funded as part of the military's war budget -- which is not subject to the budget caps that have constrained federal spending.

Thornberry said that his legislation is as much about deterring China and its actions in the South China Sea as it is about North Korea, but he's felt a new sense of urgency over North Korea's recent missile tests.

"I was surprised at how often people would come up and not just ask about North Korea, but have a real sense of concern or anxiety about North Korea," Thornberry said.