"Details of their meeting are being investigated," Gross said, adding that checks were being made to see if Atta had made other visits to the country. 
Atta, an Egyptian who studied in Germany, is believed to have been the pilot of American Airlines Flight 11, the first plane to smash into the World Trade Center. 
Asked if Atta might have been using a different name, Aziz told the L.A. Times, "Even if such an incident had taken place, it doesn't mean anything. Any diplomat in any mission might meet people in a restaurant here or there and talk to them, which is meaningless. If that person turned out to be something else, that doesn't mean he had a connection with what that person did later." 
Another Czech official, who spoke on condition of anonymity, told The Associated Press news agency that intelligence agents were checking whether Ani had also met a second hijacker. 
Government officials told AP earlier this month that Ani was under surveillance because he was suspected of being involved in a plot to attack the headquarters of Radio Free Europe. 
The radio station, partially funded by Washington, broadcasts to Iran and Iraq. Baghdad has called that an act of aggression. 
Intelligence sources tell CNN there is no known link beween the Prague meeting and the anthrax attacks since September 11.