Police are holding a British citizen at Moi International Airport in Mombasa for possessing 42 bullets.
Ms Surone Abdiwahid Faiza, 27, was stopped at the screening point at 4.10am on Thursday.
The woman of Somali origin had two magazines— one had 10 bullets of 9mm calibre and the other had 32 bullets of the same calibre.
These type of ammunitions are commonly used in small arms like pistols.
The woman was scheduled to travel to Nairobi’s Jomo Kenyatta International Airport and later board Kenya Airways Flight 625 to London.
Airport police chief Beatrice Kigalu said the bullets were concealed in a suitcase.
She said the suspect was being interrogated by anti-terror police.
"We are following to see if she had any accomplices,” said Ms Kigalu.
“We are vigilant and we have to ensure that nothing passes through our facility.”