President Barack Obama is continuing his outreach to the Muslim world in a video message marking the start of the Islamic holy month of Ramadan. The monthlong period of prayer, reflection and sunrise-to-sunset fasts begins Saturday in most of the Islamic world. In the message posted on the White House Web site, Obama says the rituals of Ramadan are a reminder of the principles Muslims and Christians have in common. He says those principles include advancing justice, progress, tolerance and the dignity of all human beings.