Obama says he regrets having to move speech inside

President Barack Obama waves as he joins Former President Bill Clinton during the Democratic National Convention in Charlotte, N.C., on Wednesday, Sept. 5, 2012. (AP Photo/Charles Dharapak)

CHARLOTTE, N.C. (AP) — President Barack Obama is telling supporters he regrets having to move his acceptance speech indoors, but says he couldn't risk their safety given the possibility of severe weather.

Obama spoke on a conference call to people who had tickets to the outdoor event. The indoor arena where Obama will speak Thursday night holds far fewer people.

The president told supporters he wouldn't "let a little thunder and lightning get us down." He says his team will do everything it can to get those supporters into other campaign events between now and Election Day.