Update 2 | 18-year-old suspect who surrendered to police has alibi
PM Manuel Valls says preventing another attack is the main concern at the moment
A woman holds up the satirical weekly Charlie Hebdo during a gathering at the Place de la Republique in Paris Wednesday
Hamyd Mourad, the man who handed himself in, has an alibi - he was at school at time, according to media reports
According to iTele, Hamyd Mourad said that at the time of the attack he was in lycée in Charleville-Mezieres. It was reported earlier that Mourad is a student.
French interior ministry spokesman Pierre Henri Brandet said that seven people had been detained for questioning, all of whom were related, or connected in some way, to the two main suspects - Cherif and Said Kouachi.
Of the two brothers Brandet said Cherif was "well known" to French authorities, and his brother Said was "less well known".
French Prime Minister Manuel Valls said that several arrests occurred overnight in relation to the shooting attack at the offices of satirical newspaper Charlie Hebdo, during which 12 people were killed.
A spokesman for the French interior ministry has told the BBC that seven arrests took place overnight. Family and friends of the two chief suspects named by police, brothers Cherif and Said Kouachi, were detained.
In an interview with RTL radio this morning, Prime Minister Valls said preventing another attack "is our main concern" as he explained why authorities released photos of the two men along with a plea for witnesses to come forward.
More information as it becomes available.
