Democrat Joe Biden has edged out Republican Donald Trump in fundraising for a second straight month in June, data from the rival US presidential campaigns showed on Wednesday.

Mr Biden and allied Democratic groups brought in over $141m during the month, while Mr Trump and closely tied groups collected $131 million.

In each case, the figures were new monthly records this year for campaigns that are expected to mount the most expensive US election in history.

Mr Biden, who waged his successful primary battle against a large field of Democrats on a shoestring budget, is trying to erase a fundraising gap ahead of the election on 3 November.

Mr Trump, who started his re-election bid shortly after he moved into the White House, has been an impressive fundraiser, managing to collect a sizeable amount for his re-election campaign against the Democrats.

Yet Mr Biden's fundraising has picked up since staking a lead in national polls after the coronavirus crisis and protests over police brutality against black Americans.

Both campaigns are proving they can stockpile significant sums despite the ongoing pandemic. The money finances television and internet advertisements, as well as staff and travel to key battleground states.

Mr Trump raised $14m online during a campaign celebrating his birthday last month.

Mr Biden, meanwhile, raised more than $11m last week at one event featuring former US President Barack Obama, which included a portion for people who contributed as little as they wished and another, more private event for high-rollers.

Read more:

Judge lifts ban on book about Trump family by niece

US election: Four months to decide the next four years 

Despite the two-month winning streak, Mr Biden and his allies are still likely at a disadvantage to Mr Trump when it comes to cash.

The Trump group reported having over $295m in cash on hand, a closely watched figure representing what they could spend.

The Biden statement did not include a comparable figure, but they have consistently trailed Mr Trump. Neither campaign's figures include the significant spending that is being done by unaffiliated political groups.