Tuesday evening's debate at Hofstra University in Hempstead, New York state, saw a more combative Obama confront Romney - mostly on domestic issues - after Obama's listless performance in their first encounter on 3 October in Denver.

The broadcaster CNN, which hosted the second debate, said its flash survey showed that 46 percent of viewers favored Obama while 39 percent preferred Romney. A CBS News poll showed 37 percent for Obama compared to 30 percent for Romney.

Analysts said Obama delivered an improved performance, with conservative American Enterprise Institute fellow Karlyn Bowman saying: "Obama is back in the game."

Linda Fowler, governmental professor at Dartmouth College, said: "I think the Republicans will be disappointed that Romney didn't put him away, and the Democrats will be reassured that the president is in full press now."

Romney tackles Obama on jobs

Romney delivered stinging indictments of Obama's economic record, accusing the president of failing to restore speedy jobs growth and cut ballooning deficits.

"The president wants to do well, I understand, but the policies he put in place have not let the economy take off as it could have," Romney said.

Obama replied that Romney had invested in companies in China that were pioneers of outsourcing of US jobs.

Obama challenged Romney repeatedly on his corporate past while also rebuking Romney over his recent criticism of the White House's handling of the attack in Libya last month when militants killed a US ambassador and three other Americans.

"The suggestion that anybody in my team, whether it's a secretary of state, our UN ambassador, anybody on my team, would play politics or mislead when we've lost four of our own, governor, is offensive," Obama said while staring at Romney.

Both candidates roamed the stage to respond directly to questioners and bickered frequently about the rules and who had exceeded his time.

With just three weeks remaining until the election on 6 November, surveys indicate that Obama has the edge. A Reuters/Ipsos daily tracking poll on Tuesday put Obama on 46 percent and Romney on 43 percent.

A Gallup/USA Today poll showed, however, that Romney was ahead by four percentage points in the 12 most contested states.

ipj/sej (Reuters, AFP, dpa)