Police in Paris on Friday arrested a man who took out a pistol and threatened commuters on one of the capital's busiest Metro lines, ligne 13. The 30-year-old unidentified man of Moroccan origin, was detained by police mid-morning between Metro stations Saint-Denis Basilique and Université.

According to an official source, he pulled out a Colt 45 and began to threaten a passenger saying "I am Mohamed Merah and I am going to kill you" in reference to the young Islamist killed by police in Toulouse three weeks ago after the murder of seven people.

The gun did not appear to be loaded, but the man was carrying two rounds of ammunition and was described as "not being in full possession of his mental faculties".

Disaster was avoided when one of the passengers pulled the emergency cord and the man used the opportunity to escape into a train tunnel where he was eventually caught by police.

The man, who refused at first to reveal his identity, is already known to the authorities in connection with a number of petty crimes.