Updated at 10:05 p.m. ET
MIDLAND, Texas - Federal authorities told CBS News that a soldier who recently served in Afghanistan was detained Saturday after trying to go through a security checkpoint at a Texas airport with what sources said were C-4 explosives.
The man, who was either returning or had recently returned from Afghanistan, was stopped at a security checkpoint at the Midland International Airport about 9 a.m. and taken into custody by the FBI, federal and local officials said.
Authorities told CBS News they do not believe the incident is a threat to national security.
A Midland Police Department source told CBS affiliate KOSA-TV in Odessa, Texas, that the explosives are C-4. Security agents found the explosives in the man's carry-on bag when it was going through the X-ray machine.
FBI spokesman Mike Martinez declined to say whether the man was in military uniform or how many explosives were found in the bag. He said he did not know where the man was being held, saying he was at either the airport or at the FBI office in Midland.
Midland police Sgt. Brian Rackow told the Midland Reporter-Telegram and Odessa American that the man identified himself to investigating officials as being active in the military. He and his family had been in the area visiting relatives and were on their way back to his base in North Carolina, Rackow said.
It's not clear which base, and Rackow did not immediately return phone calls to The Associated Press for comment.
City of Midland spokeswoman Tasa Watts said she had no information on the suspect but the explosives were wrapped in military-grade wrapping. She said the specific grade won't be known until the explosives are tested.
The Transportation Security Administration issued a statement saying one of its officers spotted a suspicious item in a carry-on bag during X-ray screening. It said the checkpoint was closed for about an hour while officers investigated and removed the item.
Watts said the man was entering a terminal when he was stopped, and a sweep was done to clear that terminal before normal operations resumed.
An American Airlines spokesman said the man had a reservation on Flight 3283 from Midland to Dallas-Fort Worth International Airport. The departure time for the American Eagle plane was 9:45 a.m.