President Barack Obama said the occupant of the White House must "work for everyone, not just for some", in a jibe directed towards Republican rival Mitt Romney, who stated he does not worry about the 47% of the country which pays no income taxes.

Mr Romney neither disavowed nor apologised for his remarks, which included an observation that nearly half of the country believe they are victims and entitled to a range of support.

Instead, Mr Romney cast his comment as evidence of a fundamental difference with Mr Obama over the economy, adding the government should not "take from some to give to the others".

Mr Obama said: "One thing I've learned as president is that you represent the entire country."

In response to Mr Romney's statement, Mr Obama said: "There are not a lot of people out there who think they are victims."

Mr Obama and the Democrats have tried to counter Republican attacks by depicting the president's challenger as a multi-millionaire who is out of touch with middle-class Americans and who has some of his substantial wealth invested overseas.

As the rivals sparred with seven weeks remaining in a close race for the White House, two Republican Senate candidates publicly disavowed Mr Romney's remarks.

Republican officials openly debated the impact a series of controversies would have on the party's prospects of winning the presidency.

Mr Romney's running mate, Representative Paul Ryan, said Mr Romney was "obviously inarticulate" in trying to make his point.

Mr Ryan said: "The point we're trying to make here is, under the Obama economy, government dependency is up and economic stagnation is up."

While the Romney campaign has been promoting its fundraising prowess for months, it acknowledged it had borrowed $20 million to boost its cash flow.