LONDON (AP) -- Three men accused of conspiring with suicide bombers who killed 52 commuters on the London transport system in 2005 pleaded not guilty during a court hearing Friday.

Mohammed Shakil, 31; Sadeer Saleem, 27; and Waheed Ali, 24, are accused of conspiring to cause explosions on London's transport network or at tourist attractions in London "of a nature likely to endanger life or cause serious injury."

The men appeared at London's Central Criminal Court by video link from prison for the pretrial hearing.

Four bombers and 52 commuters died in the attacks on July 7, 2005, when bombs carried in knapsacks exploded on three subway trains and a double-decker bus.

The three suspects are all from the Beeston area of Leeds, in northern England, which was home to several of the bombers.

Two of the men were arrested March 22 as they prepared to fly to Pakistan from Manchester Airport. The third was detained in Leeds the same day.