(CNN) -- The director of the Federal Emergency Management Agency said Thursday those New Orleans residents who chose not to heed warnings to evacuate before Hurricane Katrina bear some responsibility for their fates.

Michael Brown also agreed with other public officials that the death toll in the city could reach into the thousands.

"Unfortunately, that's going to be attributable a lot to people who did not heed the advance warnings," Brown told CNN.

"I don't make judgments about why people chose not to leave but, you know, there was a mandatory evacuation of New Orleans," he said.

"And to find people still there is just heart-wrenching to me because, you know, the mayor did everything he could to get them out of there.