NEW YORK — A New York City man was sentenced to life in prison on Friday for conspiring to form a three-man terrorist cell with two former high school classmates and spread death on the subways as suicide bombers — a foiled plot that authorities called one of the closest calls since the 9/11 attacks.

Adis Medunjanin, a 28-year-old US citizen from Bosnia, was convicted this year of conspiracy to use weapons of mass destruction, attempting to commit an act of terrorism, and other terrorism charges.