Members of the first family were fine, a White House official said, speaking on the condition of anonymity because of a reluctance to discuss personal matters involving the president.
Journalists when they returned to the secured neighborhood where Obama was staying saw an ambulance speed past with its lights on. The ambulance then left the neighborhood with a black sedan trailing.
The president was playing golf with friends from Chicago who joined him on his holiday vacation. The White House is not identifying which friend's child was injured.
After a brief delay, Obama returned to the course.
Associated Press writer Philip Elliott in Honolulu contributed to this report.