Beginning Thursday through Saturday morning, the heavily armed Metropolitan Police counter-terrorism squad raided nine residential and commercial addresses in East and North London and arrested five men and two women, the BBC said.
One of the suspects resisted arrest and officers deployed a Taser stun-gun on him, police said.
The various charges against the group include "suspicion of the commission, preparation or instigation of acts of terrorism," the BBC said.
The suspects allegedly have links to radical Islamic groups, police said.
Friday, a judge granted police permission to detain the suspects until Thursday to allow for more evidence-gathering, the report said.
Investigators said there was no indication attacks were planned on any events associated with the Summer Olympic Games, set to begin July 27.