With a local television station broadcasting his appearance live, Mr. Kerry spoke for less than three minutes before taking questions.
Mr. Sweeney wrote in bold letters that Mr. Kerry would speak to the board at the end of the vote.
When Mr. Kerry spoke, the president stood at his side, smiling and occasionally speaking into the microphone.
In a 15-minute address, Mr. Kerry spoke to the labor leaders by satellite from a factory in Chicago.
Mr. Kerry spoke after being endorsed by the International Association of Firefighters.
Mr. Kerry spoke to them, praising them for those efforts and vowing to help strengthen the Democratic Party over the next four years.
As Mr. Kerry spoke, the two campaigns also warred on the air over the black vote.
As Mr. Kerry spoke, his campaign released the letter it said had been sent to the White House.
Before Mr. Kerry spoke, Congressional Republicans were out in force.
Mr. Kerry spoke for 38 minutes.