White flags appeared atop the Brooklyn Bridge Tuesday morning, replacing U.S. flags that usually sit on top of the bridge on either side.

Authorities are investigating the security breach -- both how it happened and what it symbolizes.

White flags traditionally symbolize surrender, but questions about the intentions of the flag-placers as well as how they succeeded were all over social media Tuesday morning, according to the Wall Street Journal. 

Social media and blog posts suggested it may have been part of a movie shoot that has been going on in the area for the past week, but authorities said there was no connection, according to the Gothamist blog.

As of 11 a.m. the two flags, which appear to be U.S. flags painted white, were taken down, according to the New York Post.

Brooklyn Borough president Eric Adams, also a retired police captain, issued a statement, according to the New York Observer.

"If flying a white flag atop the Brooklyn Bridge is someone's idea of a joke, I'm not laughing. We will not surrender our public safety to anyone, at any time. Political and social expression, whatever its message may be, has a place in our society but not at the expense of others' security. I am confident in the NYPD's ability to investigate this matter," he said.

The investigation into how the U.S. flags were stolen from atop two 273-foot towers, which are supposed to be watched closely because they are high security risks and terror targets, is ongoing, according to the New York Daily News.

Each of the stolen U.S. flags are about 12 feet by 18 feet and only replaced when old or weathered by Department of Transportation crews who are specially trained to do so.

This is the second time in the recent past that the U.S. flags have been removed, according to the Daily News. In 2004 the flags were taken down and were used to barter for the release of demonstrators from the NYPD during the Republican National Convention.