NEW YORK — Two German artists have claimed responsibility for replacing American flags on the Brooklyn Bridge with faded white versions last month in a bizarre urban mystery that exposed holes in security at one of the city’s most enduring landmarks.

Berlin-based Mischa Leinkauf and Mattias Wermke said Tuesday that they hoisted the hand-sewn white flags onto the 131-year-old bridge’s neo-gothic stone towers as a celebration of public art in “the global center of creativity.” They said they switched the flags early on July 22 to commemorate the 145th anniversary of German-born Brooklyn Bridge architect John August Roebling’s death.

In a statement, the artists said they “were careful to treat the bridge and the flags with respect,” but they didn’t address potential criminal liability from the project. They said they followed U.S. Flag Code in their handling of the American flags they removed and were returning them.

The New York Police Department said it was aware of the artists’ claims but wouldn’t confirm their validity or say whether investigators had identified the artists as suspects before they came forward.

Deputy Commissioner Stephen Davis said the investigation is continuing. Detectives, he said, are trying to determine if more than two people were involved in the complex flag-switch operation.

If the artists have the flags, he said, “we certainly would love to have them back.”

Leinkauf and Wermke have scaled buildings, bridges and statues in a series of projects blurring the line of access to public works and spaces. In 2007, according to their website, they tied balloons to cables high above the Brooklyn Bridge roadway.

The day the flags went up, the police department’s counterterrorism and intelligence chief said he believed four or five people scaled to the top of the bridge’s towers and swapped the flags in the dead of night.

Deputy Commissioner John Miller said the people involved appeared to use aluminum cooking sheets to cover the lamps illuminating the American flags that usually fly there before hoisting their bleached white replacements.

Video footage of the security breach shows the people walking on the bridge’s footpath at about 3:10 a.m., and the light on the bridge’s Brooklyn tower flickers and goes dark about 20 minutes later, Miller said. The same thing happens about 12 minutes later on the Manhattan tower, he said.

Mayor Bill de Blasio has called the security breach “a wake-up call.”

The NYPD has officers stationed overseas, but Davis did not say whether there are any in Berlin. He said a potential arrest involving suspects from Germany would be done through Interpol, the international police organization.

The German artists, who first made their claim of responsibility to The New York Times, said they were flooded with media inquiries and wouldn’t be able to immediately respond to an interview request.