A police van took the men to Westminster Magistrates' Court - where they are due appear later
Five men have appeared in court charged in connection with a terror plot "to shoot, to kill, police officers or soldiers on the streets of London".
Tarik Hassane, Suhaib Majeed, Nyall Hamlett, and Momen Motasim, all from London, have been charged with intending to commit acts of terrorism.
A fifth man, Nathan Cuffy, 25, from London, faces firearms offences.
All five were remanded in custody until 27 October after the hearing at Westminster Magistrates' Court.
They will next appear at the Old Bailey.
The men, who have been jointly charged with the intention of committing acts of terrorism, or assisting others to commit such acts, between 8 July and 7 October, are:
They were charged following arrests in London over the last two weeks.
Prosecuting, Mark Dawson, told the court the case revolved around an alleged plot "to shoot, to kill, police officers or soldiers on the streets of London."
He said 21 details within the terror charge related to different individuals, but did not give specific details about which parts of the charge related to which accused.
The five men had appeared in the dock flanked by 12 police and security guards, said the BBC's Steve Swann, who was in court.
The Metropolitan Police said the men are accused of taking an oath of allegiance to the Islamic State (IS) militant group and arranging to buy a handgun equipped with a silencer and conducting "hostile reconnaissance" of a police station and Army barracks in London using Google Street View.
The terror charges also include allegations the four men set-up "methods of secret communications" and that they "entered into covert discussions".
They are accused of discussing the sourcing of a moped, along with where they could store the vehicle in Shepherd's Bush, west London.
Tarik Hassane was among those charged
The charges also allege the men conducted reconnaissance of Shepherd's Bush police station and White City Territorial Army barracks.
Police say the men are also accused of viewing and retaining images sent via Instagram of two Met Police officers and two Met police community support officers, and having "graphic images" of the beheading of Steven Sotloff.
Mr Sotloff, a US journalist, was killed by IS militants last month having been kidnapped in Syria in 2013.
Two other men, aged 20 and 21, arrested on 7 October on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism were released without charge on Monday.
Another man, arrested on the same date, was released from custody earlier. Police say evidence was submitted to the Crown Prosecution Service, which advised it was "insufficient" to bring charges "at this time".
A woman, 19, has been released on police bail until next week pending further enquiries, police said.