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US President Donald Trump and Democratic challenger Joe Biden will go head-to-head in three debates prior to the US election.

There is also one debate scheduled for their vice-presidential candidates, Mike Pence and Kamala Harris.

They are seen as being among the top political events to watch during the US election season.

The moderators for the four debates, which typically draw large TV audiences, have now been announced.

Fox News Sunday anchor Chris Wallace will host the first presidential debate on 29 September, in Cleveland.

Miami will be the host city for the second, a town-hall style debate on 15 October, moderated by C-SPAN's Steve Scully.

NBC's Kristen Welker will host the final presidential debate on 22 October in Nashville.

The sole vice-presidential debate, between Democrat Kamala Harris and Republican Mike Pence, will be in Salt Lake City, Utah on 7 October.

That event will be moderated by USA Today Washington Bureau chief Susan Page.

The US election will be held on 3 November.

How important are the debates?

Debate viewership in terms of audience share has dropped in recent years, according to the Pew Research Center, but millions of voters still regularly tune in. 

The first debate between Mr Trump and former Democratic presidential candidate Hillary Clinton was a major draw in 2016, with a reported record 84 million viewers, according to data from Nielsen Media Research. 

Almost 72 million people watched the third debate between the two. Pew Research polling also indicates that voters find the debate performances are a factor in helping them choose their preferred candidate.