MONTREAL - Police arrested a traveller at Montreal's Trudeau airport Sunday morning after sources said security agents found a powder-like substance in his carry-on luggage. As of 5:30 p.m. Sunday, Montreal police officers were outside a home in the west-end borough of Lasalle, waiting for a search warrant to enter the apartment sources said is connected to the arrest. Several police cars were spotted in the area. Sources told QMI Agency that the suspect, who is allegedly not a Canadian citizen, was travelling under a false identity and caught at the airport's U.S. security checkpoint at around 5:45 a.m. Sources said agents searched his carry-on and found what is believed to be a powder. Police have refused to say what was found in the luggage. They would not say if they foiled an attack or if the man had an accomplice or acted alone. Sixteen flights to the U.S. were delayed on Sunday after police arrested the traveller, who is in custody and being questioned. The police bomb squad arrived and closed the U.S. departure security checkpoint at the airport, leaving hundreds of passengers on standby. Police set up a security perimeter and opened a command centre. By 1 p.m. police reopened the U.S. checkpoint. No flights were cancelled. Police spokesman Jean-Pierre Brabant said the suitcase and package were sent for analysis. "We should have the results in a few days," Brabant said. Source Edmonton Sun