NEW YORK, US - TOP administration officials said on Sunday US economic growth is highly likely to resume in the second half of the year, but warned of 'hard choices' to contain rising deficits once recovery is assured.

Treasury Secretary Timothy Geithner would not rule out higher taxes in the future, telling ABC television: 'We're going to have to do what is necessary.'

Mr Geithner and White House economic adviser Larry Summers went on the Sunday television talk shows to make the case that President Barack Obama's economic stimulus program was gaining traction despite rising unemployment and worries about the US deficit.

'A very great likelihood, and this is what most professional forecasters say, is that we'll see growth going forward in the second half of this year,' Mr Summers said in an interview with NBC television.

They were seconded by former chairman of the Federal Reserve, Alan Greenspan, who told ABC the worst US financial crisis in a half a century was 'not quite' over, 'but we're getting there'. Mr Greenspan said he was 'pretty sure' the broader US economy had hit bottom and begun to turn around in mid-July.

Mr Summers pointed to the wild success of a 'cash for clunkers' program as a sign that the US auto industry was coming back to life, and said industries will have to replace inventories that have been massively cut.

But both he and Mr Geithner acknowledged that the US jobless rate will continue to climb from its current level of 9.5 per cent. The treasury secretary cited private analysts as saying it will not start coming down until the beginning of the second half of 2010.

'You are right that there are signs the recession is easing. And if you think about where we were at the end of last year - we had an economy in freefall, a financial system on the verge of collapse,' Mr Geithner said on ABC.

'But I think we have a ways to go,' he added. 'I want to emphasize the basic realities. Unemployment is still very high in this country. We need to make Americans more confident about their future.'