The weapons used in attacks in Paris that left 17 people dead came from outside the country, and authorities are urgently tracing the source of the financing, according to a French police official.

Christophe Crepin, a French police union representative, said on Tuesday that several people are being sought in relation to the "substantial" financing of the three attackers, as well as others in their network, AP news agency reported.

He said the weapons stockpile clearly came from abroad and the amount spent pointed to an organised network.

Crepin said the people in the network had mixed allegiances, with little sense of loyalty to individual Islamist groups.

The news came just hours after a Bulgarian prosecutor announced the arrest of a man with ties to one of the brothers who carried out the attack on the Charlie Hebdo satirical newspaper.

Source: Agencies