Hi guys, I just want to let you know. Singapore ask for passport period. They no longer accept US RTD or RP. I learnt the hard way. Wasting around $3k on my accomodation, detained for 22 hours and treated like criminals until I arrived back to US. They didn't even let me call my friend who has been waiting outside to pick me up. Funny thing is, I was in Singapore for a week on april 2006 using RTD.