Senior U.S. Army officials on Monday mapped out a plan to dramatically increase the range of the service's artillery and missile systems to counter a Russian threat that would leave ground forces without air support in the "first few weeks" of a war in Europe.

The Army has named long-range precision fires as its top modernization priority in a reform effort aimed at replacing the service's major weapons platforms.

"We've got to push the maximum range of all systems under development for close, deep and strategic, and we have got to outgun the enemy," Gen. Robert Brown, commanding general of United States Army Pacific Command, told an audience during a panel discussion on "improving long-range precision fires" at the Association of the United States Army's Global Force Symposium in Huntsville, Alabama.

"We don't do that right now; it's a huge gap. ... We need cannons that fire as far as rockets today. We need rockets that fire as far as today's missiles, and we need missiles out to 499 kilometers."

Currently, Russian air defenses are effective enough to keep fixed-wing aircraft from conducting close-air support; intelligence, surveillance and reconnaissance; and other support missions vital to ground combat forces, said John Gordon IV, a senior policy researcher at Rand Corp.

Rand conducted a study for officials at Fort Sill, Oklahoma, concluding that in the first seven to 10 days of a conflict with Russia, "the Russians would have very significant advantage in terms of numbers and all aspects of ground combat."

"Because of the power and the range and the lethality of these Russian air defenses, it's going to make all forms of air support much more difficult, and the ground forces are going to feel the effects," Gordon said.

"It's certainly going to put a premium on U.S. Army field artillery. It's going to put a premium on long-range fires to compensate for what will, at least initially, be a significant degradation in the amount of air support -- less joint ISR, less CAS, less interdiction, less offensive and defensive counter-air, so all that is going to have an effect on Army operations because of the quality of these Russian air defenses," he said.

Russia also has a larger number of superior artillery systems than the U.S., Gordon said.

"The Russians take this stuff seriously; artillery has been the strong suit of the Russian Army since the days of the czars," he said.

"They've got a range advantage over us in a number of different areas, particularly cannons," Gordon said. "Typically, modern Russian cannons have got 50 percent to 100 percent greater range than the current generation of U.S. cannons."

Brig. Gen. Stephen Maranian, commandant of the Army's Field Artillery School, who now leads the newly formed cross-functional team responsible for the long-range precision fires modernization priority, said the Army is looking at hypervelocity, electromagnetics and "very large-caliber cannon" to improve long-range fires in the long term.

In the shorter term, the service is working on replacing the Army Tactical Missile System, or ATacMS, with the Precision Strike Missile, Maranian said.

ATacMS, which has a range of 160 kilometers, was terminated in 2007, but the Army has since extended the service life of the program.

"We expect to see [Precision Strike Missile] prototypes fly within the next fiscal year in 2019," Maranian said. "From there, hopefully a delivery of the base missile by early 2023."

The base missile is going to provide a "huge upgrade from ATAcMs," increasing the range out to 499 kilometers, the limit of the Intermediate-Range Nuclear Forces, or INF, Treaty, he said.

"It's going to provide 1.5 times the speed, it's going to be twice the capacity ... and it's also going to have the ability to be even more lethal than the ATAcMs," he added.

Maranian said the base missile will be able to go after "multi-domain targets -- so the ability to hit a ship at sea, the ability to hit moving targets on the land domain, the ability to have sub-munitions that attack heavy armored targets and have effects ... and the ability to use sensors to hone in on targets. Those are all aspects of future spirals of this missile that the base Precision Strike Missile will provide."

In terms of artillery, Maranian said the Army is planning a "dramatic increase to the firepower" that exists in its brigade combat teams.

The Army has been attempting to upgrade its Paladin 155mm self-propelled howitzers systems. The M109A6 Paladin Integrated Management, or PIM, just completed its initial operational test and evaluation last week, Maranian said.

The Army is relying on the Extended Range Cannon Artillery, or ERCA, technology to extend the range of the system.

The upgraded, rocket-assisted projectile, which will increase the range out to 40 kilometers, is scheduled to be ready by fiscal 2021, he said.

An upgraded breech, which will help boost the range out to 70 kilometers, will be ready by the fiscal 2023 timeframe, as will be the "incorporation of an autoloader to improve our four rounds in the initial minute, and one round a minute after that, sustained rate to a six-to-10 round a minute sustained rate of fire," Maranian said.

"That will be the basis of achieving overmatch against any adversary in any theater," he said.

-- Matthew Cox can be reached at matthew.cox@military.com.