By Steve Holland and John Whitesides
ALBUQUERQUE, N.M./WASHINGTON (Reuters) - Republican presidential nominee Donald Trump pressed his attack on Democratic rival Hillary Clinton's integrity as she struggled to get past a new firestorm over her emails with just eight days to go until Election Day.
Friday's announcement by FBI Director James Comey that his agency is investigating more emails as part of a probe into Clinton's use of a private email server gave new hope to Trump that he can make an improbable comeback and win on Nov. 8.
The Clinton campaign and its supporters in the Democratic Party furiously attacked Comey for releasing information that raised questions but provided no details so close to the election. Some party leaders accused the FBI of a double standard, saying the agency was concealing damaging information about the Trump campaign.
The FBI spent a year investigating Clinton's use of a private email server, instead of government systems, while she was secretary of state from 2009 to 2013. Comey concluded in July that while Clinton and her staff had been "extremely careless" in handling classified information there were no grounds for any charges.
But the issue resurfaced unexpectedly on Friday when Comey sent a brief letter to members of Congress to tell them the agency was looking at new emails.
He said "we don't know the significance of this newly discovered collection of emails," which were found during an unrelated probe into the estranged husband of a top Clinton aide. But Trump seized on the news to charge that Clinton represents a corrupt political system.
"When we win on Nov. 8 we are going to Washington D.C. and we are going drain the swamp," he said on Sunday night at a rally in Albuquerque, New Mexico. "Hillary Clinton is not the victim. You, the American people are the victims of this corrupt system."
U.S. Senator Harry Reid, the Democratic leader in the Senate, accused Comey on Sunday of "a disturbing double standard for the treatment of sensitive information, with what appears to be a clear intent to aid one political party over another."
He said, without providing evidence, that the FBI was keeping “explosive information” under wraps about ties between the Trump campaign and Russian officials.
Democratic Representative Elijah Cummings hammered this accusation on Monday, urging the FBI to release information on Trump and his advisers’ dealings with Russia.
“Members of Congress including myself, have asked for months for the FBI to provide us with information as to whether Mr, Trump, Mr Manafort, other associates and the Russian government have any connection with each other,” Cummings told CNN, referring to a former senior Trump campaign official, Paul Manafort.
An FBI spokeswoman said late on Sunday: “When we receive the letter it will be handled through our usual process in responding to members of Congress,” referring to Reid's accusation.
The U.S. government has accused Russia of a campaign of cyber attacks targeting the Democratic Party that has led to the release of thousands of illegally obtained emails, revealing the sometimes unflattering inner workings of the party. The Kremlin has denied this. Trump has declined to implicate Russia in any wrongdoing.
Democrats have demanded that Comey and the FBI rapidly work to make public what they know about the new email trove. A source familiar with the matter said on Sunday that the FBI had secured a warrant to examine the emails.
Daily tracking polls should reflect soon whether the controversy is having an impact on the race. Early voting means that millions of Americans have already cast their ballots.
Trump had already narrowed Clinton's lead in national opinion polls and gone into the lead in a small number of the battleground states where the election is likely to be decided.
The latest emails were discovered as part of a separate probe of former Democratic U.S. Representative Anthony Weiner, the estranged husband of Huma Abedin, who is Clinton's closest aide and confidante, sources close to the FBI investigation have said.
The FBI is investigating illicit text messages Weiner is alleged to have sent to a 15-year-old girl in North Carolina.
The Wall Street Journal reported that federal agents are preparing to spend weeks examining about 650,000 emails contained on Weiner's laptop for possible links to Clinton's email use.
If Clinton wins the election, the controversy could cast a cloud over her White House transition.
Trump said the new email cache could represent a "motherlode" of emails.
Cummings said on Monday that the FBI’s vague statement on new emails related to the Clinton investigation made it impossible for Clinton to defend herself and “basically gave Donald Trump a softball to hit over the fence."
On Sunday, Clinton campaign chairman John Podesta and campaign manager Robby Mook questioned the FBI head's decision to notify Congress of the email review before he even knew whether they were significant or relevant.
Comey was appointed FBI director by Democratic President Barack Obama in 2013.
Cummings, the Democratic representative, said Comey was under intense pressure and scrutiny from Republicans in Congress after his conclusion in July that Clinton had not violated the law, so he released the new information to stave off any accusations from Republicans that he had withheld information.
(Additional reporting by Doina Chiacu, Susan Heavey and Mark Hosenball in Washington; Writing by Frances Kerry; Editing by Alistair Bell)