As the clock ticks closer to the November US presidential election, the Democratic Party is seeking to appear unified between its centrist and progressive factions in order to remove Donald Trump from the White House.

Former presidential hopeful Bernie Sanders is restarting in-person campaigning for the first time since the beginning of the coronavirus pandemic in March, targeting key battleground states such as New Hampshire and Michigan on behalf of Democratic nominee Joe Biden.

According to AP news, Spokesman Mike Casca said on Friday that the Vermont senator will hold a socially distanced, outdoor rally on Saturday in Lebanon, New Hampshire. Crowds numbers will be capped to prevent the event from becoming too large.

On Monday, Sanders will head a drive-in rally in Macomb County, Michigan — a Detroit suburb that went Republican in the 2016 election and was key in securing President Donald Trump's victory.

The senator's decision to return to the race comes as the Trump campaign has repeatedly accused Biden as being beholden to the “radical left" of the Democratic Party.

Biden, who defeated Sanders to win the primary race on a moderate platform, claims he is seeking to build a broad coalition of support from all Democrats and Republicans if possible, despite rejecting much of the progressive policy platform.

The former Vice President opposes government-funded health care in a Medicare for All' plan and rejects the sweeping demands of the 'Green New Deal' to combat climate change.

In response to direct accusations by Trump about adopting some of Sanders’ policies during Tuesday's first presidential debate in Cleveland, Biden said: “Right now, I’m the Democratic Party.”

The former Vice President has said he “beat the socialist”, referring to Sanders, when responding to the accusations from the Trump campaign.

​While Sanders acknowledges that Biden doesn’t share his support for 'Medicare for All' and other policies, he has endorsed his former primary rival as an alternative to President Trump.

“He does not agree with me, though I wish he did", Sanders said on ABC’s “The View” this week,

Since dropping out of the race in March, Sanders has staged virtual town halls and other events in support of Biden.

Following the Democratic convention in August, the senator has held over dozen online rallies to encourage voters in Kentucky, West Virginia, Iowa, Wisconsin, Colorado, Texas, Vermont, Pennsylvania, and Michigan.

He has also held virtual events focused on Latino and rural voters, urging them to back the Democratic ticket. Claiming that Trump poses an "existential threat" to American democracy, Sanders warned that the president may take advantage of delayed election results due to high numbers of mail-in ballots cast amid the pandemic to declare victory before all votes are counted.

Concerns have been raised, however, that returning to the campaign field could put the 79-year old senator's life at risk after President Trump was confirmed to have contracted coronavirus.

Those above the age of 70 or over are considered to be at a higher risk of dying after contracting the disease.

Vice President Mike Pence, 61, and Joe Biden, 77, have both tested negative for the coronavirus.

Sanders ran against Biden for the Democratic nomination in the 2019 - 2020 Democratic primary contest, initially appearing as the frontrunner to take on Donald Trump but suspended his campaign in March after Biden secured a number of victories following Super Tuesday, leaving the former vice president the presumptive nominee.