WASHINGTON - Poll results released Sunday show US President Barack Obama has widened his lead over Republican challenger Mitt Romney, giving the incumbent a clear boost coming out of the Democratic Party's convention last week.

US President Barack Obama speaks at a campaign event at the Palm Beach County Convention Center in Florida Sept 9, 2012.[Photo/Xinhua]

According to Gallup's seven-day rolling average for the past week, 49 percent of registered voters said they would choose Obama if the election was held today, and 45 percent said they would choose Romney.

The results were consistent with a Reuters/Ipsos poll, also released Sunday. It showed 47 percent of voters backing Obama, compared to 43 percent for Romney.

Ipsos pollster Julia Clark attributed the results in part to the traditional "bounce" Obama got from the Democratic Party's Convention last week.

According to Gallup, party conventions typically bump presidential candidates' support numbers up by five percentage points. But polls have shown Romney received virtually no "bounce" from the Republican National Convention late last month.

Both Romney and Obama accepted their parties' formal nominations at their respective conventions.