Obama hits campaign trail, says ready to 'pass baton' to Clinton

US President Barack Obama points to Democratic US presidential candidate Hillary Clinton during a Clinton campaign event in Charlotte, North Carolina, US, July 5, 2016. [Photo/Agencies]

CHARLOTTE, N.C. - After months on the sidelines, President Barack Obama joined Democratic presidential candidate Hillary Clinton on the campaign trail at a rally in North Carolina on Tuesday, telling voters he was ready to "pass the baton" to his former secretary of state.

Obama took the microphone in Charlotte, chanting "Hillary!" and told the crowd there had never been a candidate as prepared to be president as Clinton, his rival in 2008 for the Democratic nomination.

"I've run my last campaign, and I couldn't be prouder of the things we've done together, but I'm ready to pass the baton," Obama said, in what was likely to be the first of many trips this year on Clinton's behalf.

"I know Hillary Clinton is going to take it, and I know she can run that race," he said.

Obama was returning the favor after Clinton backed him in 2008's general election. This year, he waited while she battled US Senator Bernie Sanders for the Democratic nomination before endorsing Clinton last month once she became the party's presumptive nominee.

In Charlotte, Clinton preceded Obama, saying, "We're going to build on the vision for America that President Obama has always championed, a vision for a future where we do great things together."

The North Carolina trip came the same day that Federal Bureau of Investigation Director James Comey said the agency would not recommend that Clinton face criminal charges over her use of a personal email system while secretary of state.

White House spokesman Josh Earnest said Obama did not get advance notice of Comey's announcement and said the president would not discuss the FBI's investigation with Clinton.

Clinton's campaign welcomed the end of a probe that had cast a cloud over her campaign, but Republicans seized on Comey's criticism of what he termed Clinton's "extremely careless" handling of emails.

Presumptive Republican nominee Donald Trump, who was due to campaign in Raleigh, North Carolina, on Tuesday, criticized FBI recommendation, tweeting, "As usual, bad judgment."