WASHINGTON, March 15: An opinion survey released on Thursday showed that half of Americans want President Barack Obama to speed up the planned withdrawal of US troops from Afghanistan by the end of 2014.

Fifty per cent also worry that keeping US forces there makes the United States more vulnerable to terrorist attacks.

The USA TODAY/Gallup poll is the first taken after a US soldier allegedly went on a shooting rampage in Afghanistan on Sunday, killing 16 civilians.

One in four respondents says events in recent months, including attacks on coalition forces in the wake of the burning of Quran at a US military base, have persuaded them that the time has come for the troops to come home.

However, 21 per cent still believe that the US should stay in Afghanistan for as long as it takes to accomplish its goals, and 24 per cent support President Obama’s timetable to withdraw troops by 2014.

But 50 per cent endorse speeding up the withdrawal plans. That’s significantly higher support for a faster pullout than in previous Gallup polls, including a June 2011 survey in which one in three backed a quicker withdrawal than the president plans.

Nearly six in 10 say they’re worried that withdrawing US troops too quickly will make Afghanistan a safe haven for terrorists plotting attacks against the United States.

Nearly 59 to 35 per cent say sending troops to Afghanistan after the Sept 11 attacks in 2001 was the right thing to do.

The survey of 1,006 adults, taken on Tuesday, has a margin of error of +/-4 percentage points. A new Washington Post ABC News poll shows that most Americans believe few in Afghanistan support the US presence in their country.

This “perception bolsters public backing of a troop withdrawal”, the Post noted.

More than 60 per cent respondents believe the war is not worth its costs, nearly double the 35 per cent saying the decade-long effort had warranted the expense and lost lives.

There has been consistent majority opposition to the war for nearly two years.

The Washington Post-ABC News shows that big majorities of Democrats and independents continue to believe that the war is not worth its cost, and for the first time in polls stretching back five years, Republicans are evenly divided on whether the war justifies its price.

Also for the first time, more Republicans ‘strongly’ see the war as not worth fighting as opposed to those who say the war justifies its cost.

About six in 10 Democrats and independents demand early withdrawal, but the number slides to four in 10 among Republicans.

The New York Times noted that “at a time of rising gas prices, heightened talk of war with Iran and setbacks in Afghanistan, President Obama’s approval rating dropped substantially in recent weeks, the poll found, with 41 per cent of respondents expressing approval of the job he is doing and 47 per cent saying they disapprove — a dangerous position for any incumbent seeking re-election.”