(CNN) US Marines need to put away their cell phones, forget about their fancy coffees and get back to doing what Marines used to do -- dig a foxhole, cover up, stay quiet and be wary, the Corps' top officer says.

Speaking at a conference on the future of expeditionary warfare at the Washington-based Center for Strategic and International Studies on Tuesday, Gen. Robert B. Neller, commandant of the Marines Corps, said today's Marines have gotten a little too comfortable with modern conveniences in a way that could prove disastrous on the battlefield.

Neller said the Marines and Navy had seen exercises in which their personnel's use of mobile devices could give away positions to adversaries.

One involved a Marine Expeditionary Force (MEF), a large unit designed for front-line combat operations.

"What do you think the largest electromagnetic signature in the entire MEF headquarters emanated from? The billeting area. Why? Because everybody had their phone on. So we're going to have to take everybody's phone away from them?" he asked.

"I know that sounds silly, but it's not silly," Neller said at the conference. "So, okay, Marines: We're going to go to the field for 30 days; everybody leave your phone in the car and tell your significant other or your mom, your aunt, your uncle, that you're not going to get 75 texts each day and answer them."

The Navy has come up with plans to reduce its reliance on modern electronics to make its force harder to trace, going so far as to have sailors re-learn navigating by the stars instead of using the Global Positioning System, he said.

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But present-day society's most common tendencies can compromise those plans, the general said.

"We realized that we didn't have the right solution because, you know, Seaman Hicks decided she wanted to check her Facebook page, and so she walked out on the weather deck at night with her phone, and what's that phone got? It's got GPS. So anybody in the world is going to know there's some GPS somewhere out floating across the ocean, most probably on a ship," Neller said.

At the same time, Marines need to go back to basics as to what it means to be in the field, he said. That means leaving fixed bases, being on the move and doing so as covertly as possible.

"When was the last time ... when you saw Marines or soldiers operating in Iraq or Afghanistan when they camouflaged their face or they broke up the outline of their helmet with camouflage so they couldn't be seen? When was the last time you saw that?" he asked.

"We've been operating out of fixed positions. We have not moved across the ground. We have not maneuvered. We have not lived off the land," Neller said. "We've been eating in chow halls and drinking green bean coffee. That's pretty nice."

But that's not where the Corps needs to be on the battlefield, he said.

"You're living out of your pack, you're going to stop at night, you're going to dig a hole, you're going to camouflage, you're going to turn off all your stuff, and you're going to sit there, and you try to sleep," he said. "And you've got to be careful to not make any noise, and you're going to try to have absolutely no signature. Because if you can be seen, you will be attacked. That's the difference, and that's where we've got to get."