PARIS (AP) — The Paris prosecutor's office says French anti-terrorism forces have arrested four people, including a 16-year-old girl, and uncovered a makeshift laboratory with the explosive TATP.

The arrests Friday were in the Montpellier area of southern France. The prosecutor's office said around 70 grams of TATP were seized. The explosive, which can be made from readily available ingredients, was used in the November 2015 attack in Paris and the March 2016 attack in Brussels.

A Paris police official, speaking on condition of anonymity to discuss the unfolding investigation, said one of the suspects was believed to be planning a suicide attack.