Specialist officers are combing woodland for the third day in a search for evidence about an alleged plot to blow up passenger aircraft.
Police have cordoned off King's Wood at High Wycombe
Police have cordoned off King's Wood in High Wycombe, Buckinghamshire, close to the scene of one of last Thursday's raids when 24 people were arrested.
Scotland Yard refused to confirm claims a rifle and a handgun were found during the searches.
Twenty-three people are still being questioned about the alleged plot.
Detectives investigating the plot, in which the suspects allegedly planned to explode liquid-based explosive devices smuggled in hand luggage while in mid-flight, have until Wednesday before they need to apply for a warrant for further detention.
Searches are being conducted at several locations linked to the investigation, code-named Operation Overt.
In Pakistan up to 17 others are believed to be in custody, including Briton Rashid Rauf, who is thought to be the brother of Tayib Rauf, 22, one of those arrested in Birmingham last week.
The Home Office has refused to confirm or deny whether the government had formally requested his extradition.