The U.S. Strategic Command said there was no connection to reports of a "fireball" in the sky over Texas on Sunday and Tuesday's collision of satellites from the U.S. and Russia.

"There is no correlation between the debris from that collision and those reports of re-entry," said Maj. Regina Winchester, of STRATCOM.

The Federal Aviation Administration fielded calls from across Texas Sunday morning with sightings of a "fireball" in the sky. Callers also reported hearing an "explosion," probably a sonic boom caused from an object moving faster than the speed of sound, said Roland Herwig, an FAA spokesman.

In Williamson County, callers thought they had seen a plane crash. The Sheriff's Office even sent its helicopter out to look for wreckage.

A chief of staff for Mayor Bill White, Michael Moore, said a blindingly bright flash made its way across his windshield in a matter of seconds. It seemed nearby, but Moore realized it had to be closer to heaven than Earth to appear so clearly in the morning sky.

"It's hard to compete with the sun," said Moore.

Moore was just leaving Austin when he saw the bright blip in the sky around 11 a.m. He assumed it was an unusually large meteor.

The FAA issued a nationwide notice for all pilots and air crews to be on the lookout for "potential space debris" after Tuesday's collision. The satellites crashed nearly 500 miles above northern Siberia, creating debris clouds that will circle Earth for thousands of years and threaten numerous satellites, according to the chief of Russia's Mission Control.

The Associated Press contributed to this report.