Bloomberg has been among the few outspoken elected officials supporting the plans for an Islamic center and mosque two blocks from ground zero.
On Friday, President Barack Obama also backed the right for the developers to build a mosque there.
Over the weekend, the president added that he was not commenting on the wisdom of building a mosque close to ground zero. Some have said it is insensitive because the terrorists who struck the buildings in 2001 were Islamic extremists.
Bloomberg applauded Obama on Monday for backing the mosque. He declined to read what he called "nuances" into the president's additional remarks on Saturday.
Meanwhile, Sen. Harry Reid of Nevada on Monday became the highest profile Democrat to break with President Obama's mosque position.
In a statement, Reid said the first amendment protects freedom of religion and he respects that, but the mosque should be built somewhere else.
Critics have said the location of the mosque is insensitive because the terrorists who struck were Islamic extremists.
Reid is in a tight campaign for re-election in Nevada. His opponent, Republican Sharron Angle, earlier in the day called for Reid to say whether he agreed with Obama.