The Army chief of staff has said for years that a “megacity” fight is in the future and the Army is not prepared. A congressional subcommittee agrees and wants to know what it would take to build an urban warfare center.

The subcommittee on emerging threats and capabilities “remains concerned with the lack of Army prioritization” toward urban battle.

They want Army Chief of Staff Gen. Mark Milley to report back with a detailed plan and timeline to integrate that training into the Army, identify costs and feasibility of building an urban warfare training center and what technology and other shortfalls need to be fixed for the dense urban fight.

The language comes from the National Defense Authorization Act. The subcommittee’s recommendations must first pass a full committee vote, then match up with Senate recommendations before being voted on later this year.

Milley and other military leaders have pointed to global statistics showing urban growth and expansion. Cities such as Seoul, South Korea, growing urban centers such as Tehran, Iran and cities in the Baltic region threatened by Russia all present potential combat zones with near-peer adversaries.

And that’s a fight the United States hasn’t faced since World War II.

Experts have noted how basic equipment such as the Abrams tank isn’t geared toward fighting in narrow city streets, where it would be vulnerable.

Dense urban terrain gives adversaries skyscrapers and tunnels from which to attack, further complicating battles.

The subcommittee asked for details on the “challenges associated with vertical, subterranean and dense urban terrain.”

And the physical obstacles aren’t the only thing that they asked Army leaders to consider. Integrating joint forces and interagency groups to add to the urban fight are also outlined in the bill.