Democratic presidential hopeful Hillary Clinton extended her lead over Republican rival Donald Trump to 13 percentage points in a Reuters/Ipsos opinion poll released on Tuesday, up from 10 points at the end of last week.
The July 8-12 poll showed 46 per cent of likely voters supported Ms Clinton, the former secretary of state, while 33 per cent supported Mr Trump, a celebrity real estate developer.
Another 21 per cent did not support either candidate. That compared with 45 per cent who supported Ms Clinton and 35 per cent who supported Mr Trump in the five days to July 8.
Ms Clinton, the presumptive Democratic nominee, has mostly led in the national online poll this year.
The last time Mr Trump came close to Ms Clinton’s popularity was in early May, when his last two rivals for the Republican nomination dropped out of the race and party leaders started to line up behind his campaign.
Mr Trump, who is expected to become the official Republican nominee at the party’s convention next week, has since lost ground in the poll as he struggled to refocus his campaign from the Republican nominating contests to the November 8 general election.
Over the past several weeks, Mr Trump has faced criticism for his past business dealings and has quarrelled with Republican leaders over his rejection of international trade agreements and his promises to crack down on immigration.
Ms Clinton, meanwhile, has been dogged by criticisms of how she handled classified information as secretary of state.
Mr James Comey, director of the Federal Bureau of Investigation, said last week that Ms Clinton and her staff were “extremely careless” with sensitive information but recommended that the government not seek criminal charges against her.
Still, Americans have become increasingly positive about Ms Clinton this month, with half of likely voters now saying they have a favourable view of her, according to the poll, up from 46 per cent on July 1.
Some 60 per cent of likely voters have an unfavourable view of Mr Trump, compared with 58 per cent on July 1.
The Reuters/Ipsos poll surveyed 1,146 likely voters across the continental United States, Alaska and Hawaii. It has a credibility interval, a measure of accuracy, of 3 percentage points.
