Real estate developer Bruce Ratner, and others involved in multi-billion-dollar Atlantic Yards project, have given at least $680,000 to pet projects set up by Brooklyn Borough President Marty Markowitz, it was revealed today.

The New York Post says Nets owner Bruce Ratner and others involved in the $4 billion plan to build a sports arena and office complex, have given at least $680,000 to three non-profits set up by Markowitz.

The paper says the donations helped promote Brooklyn tourism and cultural events.

The government watchdog group Citizens Union calls the donations "a new area of potential conflicts of interest."

Markowitz defended the donations, saying that he has always been a proponent of this project and these contributions had no affect on his support.

"Make no mistake, I advocated for this project with no strings attached, no promise of any reciprocal support whatsoever," he said in a statement. "And I continue to do so adamantly because it will be a major catalyst for continuing what we call the 'Brooklyn Renaissance.'"

Markowitz says he is proud of what his non-profits have accomplished.

A spokesman for Ratner's real estate company says it is very proud to support Markowitz's charities.