President Bush asked Americans to pray Monday for victims of tornadoes that barreled through Midwestern states, and he promised swift federal aid "where help is justified."

"I express my sincerest condolences to victims of the tornadoes that ripped through Arkansas and Kansas and Missouri, Tennessee, Nebraska and South Dakota," Bush said at the top of a speech on the economy and national security.

"Our prayers and I hope your prayers are with those whose loved ones lost lives or those who lost their home," Bush told about 2,000 Republicans. "The state and local authorities need to know the federal government will be moving as quickly as we possibly can to provide help where help is needed and where help is justified."

The twisters killed more than 30 people in Kansas, Missouri and Tennessee. They also wreaked damage in several other states.

"Nature is awfully tough at times," Bush said. "The best thing we can do right now is to pray for those who have suffered."