An MP has described an armed robbery in his constituency by men believed to be brandishing handguns as an "absolutely horrifying attack".
Two balaclava-clad men entered the post office in Burwell Drive, Witney, at 09:00 BST on Saturday.
A 31-year-old from Witney has been arrested on suspicion of robbery, but searches continue for the second man.
Witney MP Robert Courts called on witnesses to help bring the "aggressive and violent" offenders to justice.
He said: "It's an absolutely horrifying attack on people who were at the heart of their community, working hard to help those around them.
"It's utterly unacceptable that people who are just going about their jobs are subjected to such violent attacks."
The offenders threatened staff during the robbery, and got away with an undisclosed quantity of cash.
The force described one of the robbers as a young man of slim to medium build wearing a black balaclava, black zip-up hooded top, black trainers and black jogging bottoms and black gloves.
Officers said the other man is 5ft 10in tall and of slim to medium build - he was also wearing a black balaclava, khaki green/grey hooded top, grey jogging bottoms and black trainers with some blue markings.
The force has not yet clarified which of the two men was being sought.
The man who was arrested has since been released under investigation.
Det Con Graham Lea said: "I believe after the incident, the offenders made off on foot along Burwell Drive in the direction of Thorney Leys, and so I am also appealing for anybody who may have dashcam or CCTV footage of these men to contact us.
"We are continuing to treat this as a top priority to locate the offenders, and there will be a continued increased police presence in the area."