French police arrest teen terror suspect

French police have arrested a 15-year old suspected of planning an attack and using encrypted social media channels to communicate with a French Islamist militant believed to be in Syria or Iraq, sources said.

In an operation led by France's domestic intelligence agency, police swooped on the teenager in Paris' eastern 20th arrondissement.

"We're working with extreme intensity to identify those we think are likely to carry out an attack," Interior Minister Bernard Cazeneuve told reporters, adding that Islamic State was recruiting "younger and younger individuals".

It is the second time a 15-year-old suspected of plotting to kill in the name of Islamic State has been arrested in five days. A source inside the prosecutor's office said both youngsters had used Telegram to communicate with Rachid Kassim, an Islamic State jihadist of French nationality.

Their arrests follow the detention of three women, including a 19-year-old, who had allegedly wanted to attack a Paris railway station using a car laden with gas cylinders.