Obama said if elected his government would "harness technology to confront the biggest challenges that America faces".

This is a core principle of my presidency - if you threaten America, you will find no safe haven.

Americans coming home, an Iran that has rolled back its nuclear program and accepted unprecedented monitoring of the program -these things are a reminder of what we can achieve when we lead with strength and with wisdom, with courage and resolve and patience. America can do and has done big things when we work together.

The Greek people are entrepreneurial.

My expectation would be that if we can begin discussions soon, shortly after the Iranian elections, we should have a fairly good sense by the end of the year as to whether they are moving in the right direction.

One thing I think we have to do is to make sure that the undocumented workers who are living in America today, that they have to take responsibility. They've got to register, pay a fine, pay their back taxes, learn English and then get on a pathway in which they could have the prospect of being here legally.

We built this country by making things, by producing goods we could sell.