He was due to lead an opposition march on Sunday but his supporters will now be marching to mourn his death.

President Vladimir Putin condemned Mr Nemtsov's murder as "vile and cynical" and vowed to find the killers.

Mr Nemtsov's allies call it a political killing linked to his opposition to Mr Putin and the Ukraine conflict.

Opposition supporters are due to gather in central Moscow at 14:00 local time (11:00 GMT) on Sunday, before marching to the spot on Great Moskvoretsky Bridge where Mr Nemtsov was killed.

Moscow city authorities had previously approved a march for up to 50,000 people but organisers said more people might now attend following the murder.

'They won't stop us'

As night fell on Saturday, flowers were piled up a metre high and two metres wide on the bridge.

Placards read: "We are all Nemtsov" and "Je Suis Boris" - the latter a reference to the Je Suis Charlie messages of support following the Charlie Hebdo killings in Paris in January.

Source: BBC