According to TMZ, she "has been warned in the strongest of terms not to perform."
The concert is set for March 26, but her security team is "strongly against" the concert, as authorities are still sifting through the wreckage from multiple attacks, which have been claimed by terror organization ISIS.
The celebrity website said there are multiple reasons for the diva to cancel the show, and one of them is simply the logistics of it. Mariah's people are concerned that the airports will be closed and the team behind the show, including Mariah, may not be able to get there.
Of course, there is the more sinister reasons, too. Her people are said to believe that the concert venue could be a target because she's an internationally famous American singer who is engaged to a billionaire (James Packer.) The concert was said to be special to Mariah, as well, since the performance would be on her birthday.
Mariah has yet to make a decision on the show. She and her people are said to be consulting with the regional U.S. Embassy and are awaiting its advice in the matter.
Other events around the city are beginning to shut down, including a scheduled performance by Italian singer-songwriter Edoardo Bennato at Royal Circus. The Belgium soccer team's practice session was also canceled hours after the attacks that, according to CNN, killed at least 30 people and wounded about 230.
Other mainstream music acts scheduled to take place over the next week are also in limbo.
Meanwhile, Warner Bros. has decided to move forward with Tuesday's London premiere of "Batman v Superman: Dawn of Justice," though the stars will not engage in the usual red carpet festivities.
"Our hearts go out to the victims of recent terrorist attacks, their families and the communities impacted around the world," a Warner Bros. statement said. "Rather than yield to terror, we've decided to join the film's fans and move forward with the London premiere of Batman v Superman this evening."