PARIS (TIP): Police SWAT teams backed by helicopters tracked two heavily armed brothers with al-Qaeda sympathies suspected in the newsroom massacre of satirical French weekly that spoofed Islam, homingin on a region north of Paris as the nationmourned the dozen slain.Authorities fear a second strike by thesuspects, who US counterterrorism officialssaid were both on the US no-fly list, anddistributed their portraits with the notice”armed and dangerous.”More than 88,000 security forces weredeployed on the streets of France.They also extended France’s maximumterror alert from Paris to the northernPicardie region, focusing on several townsthat might be possible safe havens for the two- Cherif Kouachi, 32, and Said Kouachi, 34.A senior US official yesterday said theelder Kouachi had traveled to Yemen,although it was unclear whether he wasthere to join up with extremist groups like al-Qaeda in the Arabian Peninsula, which isbased there.Witnesses said the attackers claimedallegiance to al-Qaeda in Yemen during thebloody attack Wednesday.Both were also on the US no fly list, asenior US counterterrorism official said. Theofficials spoke on condition of anonymitybecause they were not authorized to discussforeign intelligence publicly.A French security official said Americanauthorities had shared intelligenceindicating that Said Kouachi had traveled toYemen several years ago for training andFrench authorities were seeking to verify theaccuracy of the intelligence. The officialspoke on condition of anonymity because ofthe sensitivity of the matter.The worst spasm of terror violence inmore than a half-century stunned France.The lights of the Eiffel Tower went out lastnight in a tribute to the dead from theelegant iron lady that symbolizes France to the world.

At noon, the Paris Metro came to a standstill and a crowd fell silent near the Notre Dame Cathedral.

The attack struck a chord beyond French borders and similar tributes were held around Europe and elsewhere.

French President Francois Hollande -joined by residents, tourists and Muslim leaders – called for tolerance after the country’s worst terrorist attack in decades.

“France has been struck directly in the heart of its capital, in a place where the spirit of liberty – and thus of resistance -breathed freely,” Hollande said.

Nine people, members of the brothers’ entourage, have been detained for questioning in several regions.

In all, 90 people, many of them witnesses to the grisly assault on the satirical weekly Charlie Hebdo, were questioned for information on the attackers, Interior Minister Bernard Cazeneuve said in a statement.