LONDON (AP) — A British teenager has been sentenced to at least 16 1/2 years in prison for plotting a bombing whose potential targets included an Elton John concert on the 15th anniversary of the Sept. 11 attacks.

Haroon Syed had admitted planning terrorist acts at an earlier court hearing.

On Monday, judge Michael Topolski said 19-year-old Syed had been intent on "carrying out an act of mass murder in this country." He sentenced him to life with no chance of parole for 16 1/2 years.

Prosecutors said Syed tried to buy weapons and explosives online from an extremist named "Abu Yusuf," who was actually a series of British intelligence agents.

He searched online for locations, including an Elton John concert in Hyde Park on Sept. 11, 2016.