Democratic presidential nominee Hillary Clinton is surging ahead of her Republican rival, two new national election polls reveal. Clinton widened her lead against GOP nominee Donald Trump by as much as 12 points in a poll by McClatchy-Marist.

The new survey, which was conducted as Trump picked a fight with the Muslim parents of a slain US Army hero, found Clinton ahead 48% to 33%. The results marked a 12-point jump from the previous month, when the former secretary of state held a modest three-point lead, 42% to 39%.

The McClatchy-Marist poll also found that party support for the nominees was stronger among Democrats than among Republicans. The Clinton-Kaine ticket had the support of 90% of Democrats, while the Trump-Pence ticket had the support of 79% of Republicans. Slightly more Republican voters (6%) would be willing to vote for Clinton than Democrat voters (3%) for Trump.

Independent voters also leaned slightly more toward the Democratic ticket than the Republican one at 37% to 31%.

A separate poll, conducted by NBC News/Wall Street Journal, shows Clinton has nearly doubled her five-point advantage over Trump. Clinton and her running mate Tim Kaine hold the support of 47% of registered voters, while Trump and his running mate Mike Pence are supported by 38%. The Democratic nominee previously led Trump by 46% to 41%.

According to NBC News, Clinton was a favourite among women (51% to 35%), African Americans (91% to 1%), all non-white voters (69% to 17%), young voters (46% to 34%) and white voters with a university degree (47% to 40%). Meanwhile, Trump holds sway over white voters (45% to 40%), seniors (46% to 43%), independents (36% to 32%) and white voters without a university degree (49% to 36%).

The two are nearly even among male voters, with Clinton up 43% to 42%.

The new polls come on the heels of both party conventions and a hectic week for the Trump campaign. The GOP nominee not only feuded with the Gold Star family, but also publicly refused to endorse House Speaker Paul Ryan and Arizona Senator John McCain.