Anti-terror investigation begins after homemade bomb found in Paris: Sources

The Paris prosecutor has opened an anti-terror investigation after the discovery of a homemade bomb at a building in Paris and five people have been arrested, sources close to the case said.

Police discovered two cylinders of gas in the hall of a building in the city's 16th arrondissement and two others on the sidewalk. They also found a mobile phone linked to the cylinders, which appeared to be "a device to ignite" the explosive, the sources said.

A local resident alerted police after finding two of the gas cylinders around 4:30 AM (local time) on Saturday, a source close to the probe said.

According to another source, four of the suspects were being held in custody Monday night.

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The terrorist threat remains high in France which has been hit with a series of jihadist attacks since January 2015.

The latest attack was on Sunday in Marseille when a knifeman stabbed two women to death at the main train station shouting "Allahu Akbar" ("God is greatest"). He was shot and killed by soldiers.

The stabbings bring to 241 the number of people killed in jihadist attacks in France.