Nine men have denied plotting to launch bomb attacks on landmarks including Britain's Parliament and busy shopping areas.
The men were detained in several British cities Dec. 21 in the country's largest counterterrorism raids for two years.
The British suspects, aged between 20 and 29, pleaded not guilty Friday to preparing for acts of terrorism and conspiring to cause explosions.
Prosecutors accuse the men of agreeing on targets, discussing materials and methods, carrying out reconnaissance, attending operational meetings and downloading and researching files "containing practical instruction for a terrorist attack."
Several also are accused of having copies of the al-Qaida magazine Inspire.
They are due to stand trial Jan. 23 at London's Woolwich Crown Court.