UPDATED 9.02AM: New emails the FBI is examining related to Democratic presidential candidate Hillary Clinton's use of a private computer server were discovered after the agency seized electronic devices belonging to Clinton aide Huma Abedin and her husband, Anthony Weiner, the New York Times reports, citing law enforcement officials.

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With just 11 days to go before the November 8 election, FBI Director James Comey said in a letter to several congressional Republicans on Friday that the agency had learned of the existence of emails that appeared to be pertinent to its investigation.

However, he said the FBI did not know if the emails were significant and did not provide a time frame for the probe.

Republican presidential candidate Donald Trump welcomed the news.

"I have great respect for the fact that the FBI and the Department of Justice are now willing to have the courage to right the horrible mistake that they made," Trump told a campaign rally.

Trump's campaign reacted with glee. His campaign manager, Kellyanne Conway, said on Twitter that "a great day in our campaign just got even better".

US House of Representatives Speaker Paul Ryan renewed his call for US intelligence officials to stop giving Clinton classified briefing typically given to presidential candidates in the wake of the probe.

"This decision, long overdue, is the result of her reckless use of a private email server, and her refusal to be forthcoming with federal investigators. I renew my call for the Director of National Intelligence to suspend all classified briefings for Secretary Clinton until this matter is fully resolved," Ryan said in a statement referring to the former secretary of state.

The resurrection of the email issue, which has dogged Clinton's campaign from the start, dimmed a day that had featured good news for her effort to win the White House.

The Commerce Department reported that the economy grew at a 2.9 per cent annual rate in the third quarter, its fastest pace in two years and higher than the expected 2.6 per cent, thanks to a surge in exports and a rebound in investment.

The report had bolstered Clinton, who has positioned herself as the best candidate to continue years of economic expansion under Democratic President Barack Obama.

More Americans say jobs and the economy are their No. 1 priority when they decide who to vote for than any other issue.

Trump argues that as a successful businessman and political outsider, he is the best person to take a new approach to rebuilding an economy that has sent too many jobs overseas and left many Americans struggling to find decent jobs.

Clinton's camp said Friday's report showed "real progress" since Obama took office in 2009, when the country was struggling to emerge from economic recession.