WASHINGTON, March 15 (Xinhua) -- Former U.S. Vice President Joe Biden and progressive senator Bernie Sanders will face off on Sunday night in the first one-on-one debate of the Democratic primary amid the rapid spread of COVID-19.

The candidates are expected to show their leadership capabilities and crisis management skills while slamming President Donald Trump for himself and his government's response to the mounting public health crisis, local analysts said.

On Thursday, one day after Trump's national address, Biden called for making virus testing free and widely available, setting up 10 mobile sites and drive-thru facilities per state, as well as more transparency from the White House on testing, according to a report from The Hill.

Sanders addressed the outbreak in a separate speech on Friday, using the outbreak as an opportunity to push his signature promise "Medicare for All", saying his proposal would ensure free vaccines and treatment to those with such a virus.

In response, the Trump campaign accused Biden of politicizing the outbreak while calling Sanders's approach "the wrong prescription."

The two-hour debate was moved from originally planned Phoenix, Arizona, to Washington, D.C. and would no longer have audience over public health concerns.

Biden currently leads in the Democratic race over Sanders.