Who is Paul Whelan, the ex-US Marine jailed in Russia?

Following the release of basketball star Brittney Griner from Russian captivity, US President Joe Biden faces fresh questions about another imprisoned American: former US marine Paul Whelan.

Mr Whelan, 52, was given a 16-year jail sentence in 2020 after being arrested in Moscow on suspicion of spying in 2018.

The Michigan native was not part of the prisoner swap which saw Ms Griner exchanged for convicted Russian arms dealer Viktor Bout - an omission that his brother has called a "catastrophe for Paul".

At a news conference on Thursday, President Biden said that the US government will "never give up" on securing Mr Whelan's release.

Here's what we know about Mr Whelan and his case.

Who is ex-Marine Paul Whelan?

Mr Whelan is a citizen of four countries - the US, Canada, the UK and the Irish Republic.

From Novi, Michigan, he was born in Canada to British parents and moved to the US as a child.