A leading daily tracking poll, the USC Dornsife/Los Angeles Times tabulation, on Monday showed Donald Trump up by nearly 4 points over Hillary Clinton.

The result comes three days after the FBI announced it was reopening its investigation into Clinton's handling of classified information while she was secretary of state.

FBI Director James Comey, who last summer revealed that Clinton was "extremely careless" in her handling of the nation's security secrets but nonetheless did not refer charges, said new evidence had come to his attention as part of another investigation.

The FBI found a trove of 650,000 emails from the account of Clinton aide Huma Abedin on a computer owned by Abedin's estranged husband, former Rep. Anthony Weiner. The FBI is investigating Weiner on an allegation of sexting with a minor.

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The USC/Times polling had Trump at 46.6 percent support to Clinton's 43.2. And while other polls still had Clinton in the lead, they showed the margin narrowing rapidly. The most dramatic shift was in the Washington Post/ABC News poll, which had Clinton up by 12 a week ago but only 1 point ahead in its latest count.

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The IDB-TIPP tracking poll showed Clinton up 1, and Rasmussen Reports had Clinton up 3.

"Clinton's lead shrinks to 1 point as voters react to the FBI's email bombshell," the IDB report said.

The Rasmussen survey noted the two candidates have been within 2 points or less of each other nationally all last week in a survey with a plus or minus 2.5 percent margin of error.

"In a survey less than two weeks ago but before the latest FBI announcement, 70 percent of voters said Clinton's mishandling of classified information is important to their vote for president, and 53 percent disagreed with the FBI's decision in July not to seek a criminal indictment against her," the report said.

At Hot Air, blogger Allahpundit wrote, "Trump's average in the four-way race now is the highest it's been all year.

"His previous best, the day of the first presidential debate, was 41.5 percent. His crapola performance that night plus a heap of scandal in the following weeks kept him durably below that number for a solid month – until today, when he's up to 41.6 percent and seemingly still rising.

"In any other year, for any other major-party nominee, topping out at 42 percent would be known in professional parlance as 'hot garbage' but Trump has the good fortune to be running against a candidate who is herself terrible.

"With her lead down to 3.4 points, I think this Harry Enten tweet perfectly cpatures the suspicion knowing at the pros right now: 'Whoa, Chicago Tribune writer: Democrats should tell Hillary to step aside.'"

The blog post continued: "It's not so much that they expect Trump's surge to carry him past Clinton in the national average – although stay tuned – as that, if he narrows her lead to two points or so on the final weekend, the odds that the polls are wrong by pure chance and that Trump will pull the upset become much higher. Ten days ago, to believe he had a chance of winning, you had to believe that national polls were off by six points, a number outside the margin of error in many surveys. That would be a catastrophic miscalculation. A two-point lead, though, is within the MOE of most surveys, essentially making the race a toss-up."

Allahpundit said the FBI investigation issue suddenly has reminded voters "what they don't like about her rather than what they don't like about him."

In key battleground states, Trump was up by 7 in Georgia, 4 in Nevada and 2 in North Carolina. Clinton's once sizeable lead in Pennsylvania was down to 2 and in Colorado just 1.

In the key state of Florida, the New York Times showed Trump surging 46 percent to 42 percent.

Trump has also increased his lead over Clinton in Indiana where he is now up by 11 points, according to the latest Monmouth University Poll conducted from Thursday through Sunday.

Among Indiana voters who are likely to cast ballots in November's presidential election or who have already voted early, 50% currently support Trump and 39% back Clinton while another 4% intend to vote for Libertarian Gary Johnson.

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