WASHINGTON - US Vice President Kamala Harris, who has garnered wide support to become the Democratic presidential nominee, holds a two-percentage-point lead over Republican nominee Donald Trump, according to the latest poll.

In a Reuters/Ipsos survey conducted on Monday and Tuesday, one of the first following incumbent President Joe Biden's exit from the race on Sunday, Harris leads Trump by 44 percent to 42 percent, a margin within the poll's error range.

Harris, 59, is viewed as "mentally sharp and capable of handling challenges" by 56 percent of registered voters, compared to 49 percent for Trump, 78.

On Monday, Harris announced that she had secured enough support from her party, just a day after Biden withdrew from the race under growing pressure from Democrats concerned about his age and mental fitness to serve another term.

A PBS/NPR/Marist survey conducted on Monday shows Trump leading Harris 46-45 percent, with 9 percent of respondents undecided.

The poll further indicates that 41 percent of Americans, including 65 percent of Democrats, believe Biden's departure improves the Democrats' chances of winning in November.

In her first presidential campaign rally in Milwaukee, Wisconsin on Tuesday, Harris framed the choice between herself and Trump as one between "freedom, compassion, and the rule of law" versus "chaos, fear, and hate".

"Donald Trump wants to take our country backward," she told a cheering crowd.

Meanwhile, Trump expressed confidence in his ability to beat Harris during a conference call on Tuesday, offering to engage in "more than one debate" with her. He spent much of the call criticizing Harris' record on immigration and border issues, according to US media reports.