PARIS (AP) -- Police SWAT teams backed by helicopters tracked two heavily armed brothers with al-Qaida sympathies suspected in the newsroom massacre of a satirical French weekly that spoofed Islam, homing in Thursday on a region north of Paris as the nation mourned the dozen slain.

Getty Images
Getty Images
Getty Images

Authorities fear a second strike by the suspects, who U.S. counterterrorism officials said were both on the U.S. no-fly list, and distributed their portraits with the notice "armed and dangerous." More than 88,000 security forces were deployed on the streets of France.

They also extended France's maximum terror alert from Paris to the northern Picardie region, focusing on several towns that might be possible safe havens for the two - Cherif Kouachi, 32, and Said Kouachi, 34.

A senior U.S. official said Thursday the elder Kouachi had traveled to Yemen, although it was unclear whether he was there to join up with extremist groups like al-Qaida in the Arabian Peninsula, which is based there. Witnesses said the attackers claimed allegiance to al-Qaida in Yemen during the bloody attack Wednesday.

Both were also on the U.S. no fly list, a senior U.S. counterterrorism official said. The officials spoke on condition of anonymity because they were not authorized to discuss foreign intelligence publicly.

A French security official said American authorities had shared intelligence indicating that Said Kouachi had traveled to Yemen several years ago for training and French authorities were seeking to verify the accuracy of the intelligence. The official spoke on condition of anonymity because of the sensitivity of the matter.

The worst spasm of terror violence in more than a half-century stunned France. The lights of the Eiffel Tower went out Thursday night in a tribute to the dead from the elegant 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.

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