People in European and Muslim countries see US policy in Iraq as a bigger threat to world peace than Iran's nuclear programme, a survey has shown.
The survey by the Pew Research Group also found support for US President George W Bush and his "war on terror" had dropped dramatically worldwide.
Goodwill created by US aid for nations hit by the 2004 tsunami had also faded since last year, the survey found.
The survey questioned 17,000 people in 15 countries, including the US.
The latest in a series of annual polls by the Pew Global Attitudes Project interviewed respondents between 31 March and 14 May 2006.
Its release coincides with a surprise visit by President George W Bush to Baghdad in an effort to shore up support for US policy in the region.
The latest survey shows the worldwide reputation of the US continues to suffer over its prosecution of the "war on terror".
Sharp declines in the public perception of the US were particularly apparent in India, Spain and Turkey.
Goodwill towards the US had fallen from 71% to 56% in India, from 41% to 23% in Spain and from 23% to 12% in Turkey.
A majority of people in 10 of the 14 countries outside the US surveyed said the war in Iraq had made the world a more dangerous place.
Some 60% of people in the UK, which is the US biggest ally, felt the Iraq war had made the world less secure, while some 30% said it had made the world safer.
According to the survey:
- Worldwide support for the "war on terror" has remained the same or declined
- European confidence in Mr Bush has sunk even lower than it was last year
- A majority of people in most countries feel the US will not achieve its goals in the "war on terror"
- The survey also found little remaining evidence of the goodwill the US had earned over its aid for victims of the 2004 Indian Ocean tsunami.
In Indonesia, a major recipient of US tsunami aid, favourable opinions of the US had fallen from 38% in 2005 to 30% this year.
"Last year we saw some good news in countries like Russia and India," Andrew Kohut, director of the Pew Research Centre, told the Associated Press news agency.
"That good news being wiped away is a measure of how difficult a problem this is for the United States."
According to the survey, people in the US and Europe have grown increasingly concerned in the last year over Iran's nuclear programme.
The US has accused Iran of seeking to build a nuclear bomb - but Iran says its nuclear programme has a purely civilian objective.
Almost half of the Americans surveyed, 46%, viewed the current government in Iran as a "great danger" to stability in the Middle East and to world peace - a figure that has risen from 26% in 2003.
In Germany, Spain, France and the UK, the percentage of people who regard Iran as a great danger is roughly three times greater than it was three years ago.
However, the poll showed public opinion in predominantly Muslim countries was far less troubled by Tehran's nuclear programme.
Muslim people also appeared less concerned than Europeans and Americans by the victory of the Hamas militant group in Palestinian elections earlier this year.
The survey found concern over bird flu was largely confined to Asia, while two-thirds of people surveyed in each country said they were worried by global warming.
Concern over the greenhouse effect was highest in India and Japan and lowest in the US and China.
The survey interviewed people in China, Egypt, France, Germany, Great Britain, India, Indonesia, Japan, Jordan, Nigeria, Pakistan, Russia, Spain, Turkey and the US.
Its margin of error was two to six percentage points.