Americans shot in Mexico 'were CIA employees'

Mexican officials said two Americans wounded in a shooting attack by police on a US embassy vehicle were CIA employees who had now returned home.

US officials would not confirm which agency the men worked for or say what work they were performing in Mexico. President Felipe Calderon has promised a "thorough investigation with all rigour and severity" into the shooting last Friday.

The Mexican navy has said the Americans were visiting a training course being held in a rural mountainous area south of Mexico City.