This week Marines with the 13th Marine Expeditionary Unit will conduct urban exercises and drills in Phoenix and its suburbs ahead of an upcoming deployment.

It won’t be the full MEU, just 100 Marines coming from Camp Pendleton, California, Capt. Daniel Vacchio told Arizona newspaper The Republic.

“We don’t want people who have been living here and working here to be afraid,” Vacchio said. “If you see aircraft or Marines, you can safely assume it’s us.”

Though Marines and soldiers have dedicated urban training facilities on both coasts and a large complex at an Indiana National Guard training complex, moving around conventional cities, where people live, is hard to replicate.

Both Marine Corps Commandant Gen. Robert Neller and Army Chief of Staff Gen. Mark Milley have shifted resources, training, equipment and updated doctrine to the urban battle. With population growth mostly concentrated in dense urban areas or what have also come to be called “megacities” the two leaders and their contemporaries have been clear ― none of the U.S. forces are truly prepared for a sustained battle in an urban area.

Real-world scenarios are not far off, with North Korea threatening Seoul, Russians antagonizing the Baltic States and the capital of Nigeria, Lagos, set to double in size in the coming decades, officials have said.

The Marines in the Phoenix area this week will be working on a series of exercises called “Realistic Urban Training,” Capt. Diann Rosenfield told the newspaper.

The training shouldn’t disrupt area residents’ morning commute, as it will be contained to restricted areas, she said.

The drills will come with short notice, giving the Marines their mission only a few hours before they step off.

The 13th MEU typically deploys to the Western Pacific region for its rotation to support geographic combatant commanders such as Pacific Command and Central Command, depending on ongoing operations.