Clinton and Trump chase last-minute support on US election eve

US President Barack Obama campaigns for Hillary Clinton at the University of New Hampshire Durham November 7, 2016. [Photo/Agencies]

With only hours left before Election Day, the Clinton campaign was boosted by Sunday's unexpected announcement by FBI Director James Comey that the agency stood by its July decision not to press any criminal charges in an investigation of Clinton's email practices while she was secretary of state.

The latest opinion polls tapping into popular support for each candidate rather than Electoral College support, showed former Secretary of State Clinton narrowly ahead: a 5 percentage point lead over Trump nationally - with 44 percent to 39 percent support, according to latest Reuters/Ipsos poll.

Races in Florida and North Carolina were shifting, however, from favoring Clinton to being too close to call.

Clinton who is trying to become the first woman elected to the White House, had a 4 percentage point lead over Trump in separate polls by Fox News and CBS News that were released on Monday.

Financial markets brightened in reaction to the latest twists in what has been a volatile presidential campaign. Global stock markets surged, as did the US dollar, putting them on track for their biggest gains in weeks, as investors saw Sunday's announcement by Comey as boosting Clinton's chances of winning.

Clinton's comfortable lead had eroded since late last month and investors had been unnerved by the tightening race, preferring what is seen as a known quantity in Clinton, over the political wild card, Trump.

While opinion polls show a close race, but tilting toward Clinton, major bookmakers and online exchanges were more confident of a Clinton victory. PredictIt put her chances of capturing the White House at 81 percent.

Victory is earned not by winning the popular vote, but by coming first in the Electoral College system which awards the White House on the basis of state-by-state wins, meaning a handful of states where the race is close assume an outsized importance.