Military officials said they are investigating the conduct of a U.S. Marine who was on assignment for President Obama’s trip to the Netherlands last week, after witnesses said he was talking in detail about his job and passing around his government security badge during a night of drinking at a bar.

The Marine, Korey Nathan Pritchett, was first identified by a Dutch newspaper based on witness accounts and smartphone photos taken during the partying, which happened two nights before Obama arrived at The Hague for a nuclear security summit. The Washington Post confirmed and expanded on that reporting through interviews, social media postings and public records.

The Marine Corps began investigating the alleged behavior after The Post inquired about Pritchett. The Marines did not confirm whether he is the person in the photos.

Pritchett is a security guard at the U.S. Embassy in Monte­negro and reports to the State Department, according to department and military officials. He was on temporary assignment for the Netherlands summit, officials said.

Circulating an official pass that would allow someone to gain entry to the summit would be a serious security breach, according to officials and experts. Marine Corps Capt. Eric Flanagan also said that flashing a badge, drinking heavily and calling attention to your mission could jeopardize an employee’s security clearance.

Marine Korey Nathan Pritchett, right, with an unidentified partygoer, in the Netherlands, in the early morning hours of March 23. (Obtained by The Washington Post)

“Whether you’re a Marine stateside or working for the State Department, we expect nothing less than total professionalism — on and off duty,” Flanagan said. “When you are on jobs of a sensitive nature, and this is one of them, that’s definitely frowned upon. We take this very seriously.”

Flanagan said that the Marine Corps inquiry is in its early stages and that authorities do not know whether any military rules were violated. He said Pritchett was not available to comment.

Pritchett did not respond to a detailed request for comment sent to his Facebook account. A reporter was blocked from further access after the inquiry.

The incident follows a case last week in which three Secret Service agents were placed on administrative leave and sent home from the Netherlands after a night of heavy drinking, which ended with one of them passed out in a hallway of his hotel hours before being scheduled to go on duty.

The Secret Service and other agencies responsible for providing presidential protection have struggled with behavioral problems during overseas trips. In 2012, a dozen Secret Service employees, 10 members of the military and one Drug Enforcement Administration agent were sanctioned for misconduct for heavy drinking and hiring prostitutes before a regional summit in Cartagena, Colombia.

The latest case came to light in the coastal town of Noordwijk, Netherlands, where Obama stayed overnight last Monday. De Telegraaf, the nation’s largest newspaper, found local residents who said an American had been bragging about his role in protecting Obama and passing around his security badge while drinking at a club. The publication also found a witness who had smartphone photos of the American. De Telegraaf shared its initial findings with The Post.

According to witnesses interviewed by The Post, Pritchett and two colleagues began drinking at Club 19 in Noordwijk just after 12 a.m. on March 22, less than 48 hours before Obama was scheduled to arrive in the area. The trio said they were partying before reporting for duty for the summit and became progressively more intoxicated, patrons and a bartender said.

The bartender confirmed that the man in a photo taken that night was one of the Americans who had been at the club early March 22. He had talked about being a “bullet catcher” who was supposed to protect the president and described his team’s work as counter-assault.

“He said something happens, a bullet comes, he has to jump in between,” said Vasco Miguel Dos Santos, a local who had smartphone pictures from that night and said he drank with Pritchett.

He said the Marine was intoxicated but likable and entertaining with his stories. He lifted his shirt in the bar to show everyone tattoos that commemorated his tour in Afghanistan, Dos Santos said.

“I watch American movies, I know how they are,” he said. “American people are always showing off.”

Pritchett’s two colleagues left Club 19 for their hotel before 3 a.m., saying they could drink no more, said the bartender, who spoke on the condition of anonymity to discuss the customers. The Marine then went to an after-party that a Dutch woman he met in the bar invited him to, the bartender and the club’s owner said.

Dos Santos, who said he also went to the party, said they drank whiskey and cola until daybreak. The photos Dos Santos provided to The Post show Pritchett posed for smartphone pictures with a woman and other guests, who were wearing his security badge around their necks.

One of the photos was taken just before 6 a.m. on March 22, according to a digital time stamp in the file. Dos Santos and other witnesses said the man in the photos identified himself as Pritchett and they said his credentials had his name and picture on them. Some of the partyers said they also traded Facebook information with Pritchett. The man shown in the photo matches pictures on Pritchett’s Facebook page.

Pritchett left the party about 6:30 a.m., Dos Santos said.

A Secret Service spokesman said that diplomatic security guards do not work as replacements for Secret Service personnel. Only trained agents serve on counter assault or any other portion of the immediate protective detail for the president, vice president, first lady and other White House officials, the spokesman said.

State Department spokeswoman Pooja Jhunjhunwala referred questions about the incident to the military.

A former Secret Service agent with significant foreign travel experience said he was shocked by the description of the behavior.

“This is the opposite of operational security,” said the former agent, who spoke on the condition of anonymity to discuss internal security procedures. “You could be totally compromised. How difficult would it be for the girl to give the badge to a friend and they go counterfeit it in 30 minutes and give back the badge before you even notice? Taking photos with the credential — that’s not going to fly.”

Emiel van Dongen in Noordwijk, Netherlands, and Julie Tate in Washington contributed to this report.