Weird Tax Question: RRSP vs IRA

I live in the US but work in Canada. By law I can buy RRSP in Canada and that amount is tax free.
However, I need to file tax returns in the US too. I am just wondering if I can directly use my RRSP contribution as IRA deduction. By definition, they are the same thing but I don't know if IRS would allow me to do that.
Thanks a lot in advance for your help
Martin