US President George W Bush has welcomed falling petrol prices as "good news" but said he did not want the decline to put off work on alternative fuels.
President Bush has warned against petrol complacency
Speaking to a renewable-energy conference, he said he was worried it would make Americans complacent about their future as regards energy.
US petrol prices are now at their lowest level since February after falling back from highs in August.
They have mirrored falling oil prices, which have dropped 20% since July.
Then the price of crude oil hit a record high due to the fighting in Lebanon.
The average US price of petrol is now $2.26 a gallon, compared to $3.04 in August.
"Let me just put it bluntly: We're too dependent on oil," Mr Bush told the conference in St Louis.
"Low gasoline prices may mask that concern.
"I believe so strongly that this country has got to use its talent and its wealth to get us off oil.
"Probably the fastest way we can begin to change the consumer habits is to promote hybrid vehicles."
Global crude prices remained below $60 a barrel on Thursday.
Oil producers group Opec has yet to agree on its mooted cut in production to shore up prices.