President George W Bush says the US economy has a "strong foundation" but has warned Americans that continued growth cannot be taken for granted.
The president said lower taxes were important in times of uncertainty
Challenges confronting the economy included a downturn in the housing market, high energy prices and turmoil in financial markets, he said.
Mr Bush also said taxes should be kept low in a time of economic uncertainty.
His comments come after a report last week showed that US unemployment had hit a two-year high in December.
"We have a strong foundation in our economy, but we can't take economic growth for granted," Mr Bush said while speaking in Chicago.
"Recent economic indications have become increasingly mixed," he told the Union League Club of Chicago, a private club in the city's financial district.
Treasury Secretary Hank Paulson also predicted slower growth in a speech on Monday and said that there was no simple solution to the US housing market crisis.
The Bush administration is considering an economic stimulus package that could include tax cuts to prevent the economy from falling into a recession.
Mr Paulson said no decision had been made.
"The administration is focused on what steps might be taken to further strengthen the economy," Mr Paulson said.
Friday's report on the US labour market raised concerns that the US economy was heading for recession.
It showed that 18,000 jobs were created in December - many fewer than economists were expecting - and that unemployment had risen to 5%.
There was also evidence that spending was weak over the holiday period, which, combined with near-record oil prices, could prompt a sharp slowdown this year, economists said.
Some now expect policy makers at the Fed to cut interest rates by as much as half a percentage point when they meet later this month.
A quarter point cut, to 4%, is seen as almost certain.