A service member wears a patch that says "Make Aircrew Great Again" as they listen to President Donald Trump speak to troops at a Memorial Day event aboard the USS Wasp, Tuesday, May 28, 2019, in Yokosuka, Japan. The patch includes a likeness of Trump. (AP Photo/Evan Vucci)
CNN  — 

The Navy is conducting a review to examine whether President Donald Trump-themed patches worn by sailors on their uniforms during the President’s visit to the USS Wasp violated Navy rules.

“Navy leadership is aware of the incident and reviewing to ensure the patch doesn’t violate DoD policy or uniform regulations,” US Navy spokesperson Lt. Sam Boyle told CNN.

Several service members aboard the USS Wasp were seen wearing the patches when Trump addressed sailors on Tuesday. The patches showed a Trump-like image and the slogan “Make Aircrew Great Again.”

During his visit and Memorial Day speech, Trump praised the US military as the strongest in the world and polled the crowd as to whether they preferred steam-powered or electric catapults that help launch jets off the decks of aircraft carriers, saying a recent cost overrun had caused him to deem the old method – steam – preferable.

The Wasp has neither type of catapult system.

Military personnel often wear unofficial unit patches, sometimes imbued with humorous images, as part of an effort to build unit cohesion and morale.

However, service members are prohibited from exhibiting political messages while in uniform.

Unit commanders are usually responsible for ensuring that the unofficial patches do not violate military regulations

Department of Defense guidelines say that “active duty personnel may not engage in partisan political activities and all military personnel should avoid the inference that their political activities imply or appear to imply DoD sponsorship, approval, or endorsement of a political candidate, campaign, or cause.”

In December, Trump signed “Make America Great Again” hats in Iraq and during a stop at Ramstein Air Base in Germany.

A US military official told CNN the MAGA hats that Trump signed at the event in Germany were personal and brought there by military personnel in hopes of getting an autograph.

The official contended that it was not a campaign event and that the hats were used as support for Trump, not as a statement of political support.

Although the event was not an official Trump reelection campaign event, the President did declare his candidacy for reelection in 2020 soon after his inauguration.

White House press secretary Sarah Sanders told CNN the hats were personal items brought by the troops in Iraq and Germany. Sanders said the White House did not distribute them.

CNN’s Kevin Liptak contributed to this report.