Manhunt for Charlie Hebdo Attack Suspects Continues

PARIS — The French authorities carried out an intense manhunt on Thursday for the two brothers who are suspected of mounting the deadly terrorist attack on the Paris office of the newspaper Charlie Hebdo that left a dozen dead. Officials detained and questioned seven people overnight in connection with the assault.

Xavier Castaing, a spokesman for the Paris police, said that two men who resembled the suspects had been spotted in the Aisne region northeast of Paris. News reports said that the two men who were seen there had robbed a gas station, and that police forces were swarming the area, searching for the car they were using.

Even as France observed a moment of silence in remembrance of the victims of the Wednesday attack, there were unnerving reports on Thursday of the killing of a police officer and a street sweeper in a southern Paris suburb, and accounts of attacks on mosques in other parts of France.

Prime Minister Manuel Valls of France said in an interview on RTL radio that the authorities’ main concern was preventing another terrorist attack. He issued a plea for witnesses to contact the police with any relevant information.

The two chief suspects in the Charlie Hebdo attack were identified as Said Kouachi, 34, and his younger brother Chérif, 32. The authorities searched for them on Thursday across a wide area of northern France. A third suspect, Hamyd Mourad, 18, turned himself in at a police station in Charleville-Mézières, about 145 miles northeast of Paris.

Bernard Cazeneuve, the interior minister, confirmed that seven people were detained overnight in connection with the case, but he offered no details on their ties, if any, to the Kouachi brothers.

Two American officials said on Thursday that the Kouachi brothers had ties to Al Qaeda’s affiliate in Yemen, but the officials declined to say whether that meant the suspects had been in communication with the group or had traveled there and perhaps received training. The officials cited the ongoing investigation.

A recent issue of Inspire — the propaganda magazine published by the affiliate, Al Qaeda in the Arabian Peninsula — named Charlie Hebdo’s editor, Stéphane Charbonnier, on a suggested hit list of Westerners who it said had insulted the Muslim faith. His name was in a two-page spread under the heading, “A Bullet a Day Keeps the Infidel Away — Defend the Prophet Mohammed.” Mr. Charbonnier was killed in the attack.

People across France stood in silence at noon in their offices and in public places on Thursday to remember the victims of the attack, one of the worst in France since World War II.

In a national day of mourning, bells tolled. Children at schools stopped classes. Corporate boardrooms cut short meetings. The Paris Métro came to a halt. At mosques, people bowed their heads. Even some electronic road signs displayed the words “I am Charlie,” the unofficial slogan of supporters of the newspaper and its fallen staff members.