The world-famous opera house was forced to stop a performance of Rossini's "Guillaume Tell" during the second intermission because of the incident. The rest of the performance was subsequently canceled. Met spokesman Sam Neuman confirmed the incident.

New York anti-terrorism police stormed the hall in the Lincoln Center. However, there were no arrests made at this point. A police spokeswoman said the person who had sprinkled the powder fled the scene and was being sought. The nature of the powder was not known.

Unconfirmed reports said that one person at the opera house had requested medical attention. No details were given on that person's condition, the Associated Press said.

Curtains remain down

The Met meanwhile announced that it had also canceled the evening performance of another Rossini opera, "L'Italiana in Algeri" while authorities continued with their investigation.

Since the attacks on New York on September 11, 2001, the city and its institutions have been on constant alert. More recently, a small bombing in Manhattan's Chelsea district highlighted the city's vulnerability once more.

The Lincoln Center, which houses New York's Metropolitan Opera, says that it systematically checks audience members for weapons or other dangerous items.

ss/jm (AP, AFP)