A West Virginia airport terminal was evacuated after two bottles of liquid found in a woman's carry-on luggage twice tested positive for explosives residue, a Transportation Security Administration spokeswoman said.
"It looks like there were four items containing liquids," said TSA spokeswoman Amy von Walter on Thursday. "Two of those containers tested positive."
A machine that security checkpoint screeners use to test for explosives registered positive, and a canine team also got a positive hit, von Walter said.
Officials were conducting field tests on Thursday night, said Capt Jack Chambers, head of the State Police Special Operations unit. The TSA screening looks for a range of explosives residue, some of which can be found on common household items, said TSA spokesman Darrin Kayser.
Larry Salyers, manager of Tri-State Airport, said he was told the woman was a 28-year-old of Pakistani descent who had moved to Huntington, West Virginia , from Jackson, Michigan. He did not know how long she had lived in Huntington.
The woman was still at the airport late on Thursday afternoon but was not under arrest, said FBI spokesman Jeff Killeen. Commercial airline service was suspended, and about 100 passengers and airport employees were ordered to leave the terminal, said Tri-State Airport Authority President Jim Booton.
Two airlines - Comair and US Airways Express - serve the airport. Comair had to cancel at least one flight, but an early evening flight from Cincinnati was expected to arrive on time, a spokeswoman said.
A US Airways spokeswoman said one of its flights was diverted to Charleston's Yeager Airport about 60 miles (100 kilometres) away. A screener noticed a bottle in a woman's carry-on bag as she was going through security before her morning flight to Charlotte, North Carolina, Booton said.
One bottle contained a gel-type facial cleanser, FBI spokesman Jeff Killeen said.
"Anytime a prohibited item is brought to a checkpoint, then you are going to be immediately more interested in that bag," Kayser said.
The flight was allowed to leave for Charlotte, and the terminal was then evacuated, officials said.
The woman had purchased a one-way ticket to Detroit by way of Charlotte on Wednesday, Salyers said.
US authorities banned the carrying of liquids onto flights last week after British officials made arrests in an alleged plot to blow up US-bound planes using explosives disguised as drinks and other common products.