What are the financial offer or opportunities for international PhD students in US and UK? I'm an undergraduate student in Physics and Mathematics, who plans to do a PhD in Physics or Mathematics. I know when you are doing a PhD, you can be a TA or RA if it is provided, so that you can handle financial issues or you could be accepted into the PhD program with funding or scholarship (I don't remember the correct term) but what about loans or any other financial support for international PhD students in US and UK?

By the way, if it any helps, wherever I go for PhD, I will take their citizenship, at least apply, since I have no intention going back to Turkey.

A side question: Apart from the loans, what is the general procedure for financial offer from the universities? I mean how does it work?

Note: I'm from Turkey.
In the US, financial aid from the US government under Title IV of the Higher Education Act (student loans, Pell grants, and work study) is available only to US citizens and permanent residents (and a small number of other categories of people who have some permanent status in the US.)  Generally, foreign graduate students aren't eligible for this kind of aid.  

Typically, individual academic departments make decisions on who to admit and who to offer teaching/research assistantships.  If a department decides to offer you admission with an assistantship, you'll typically receive an offer letter from the institution describing the aid in detail.