Prominent Black Lives Matter activist Sasha Johnson is critically ill after being shot in the head, her party says.
The Taking the Initiative Party said she was being treated in intensive care after being “brutally attacked” in the early hours of Sunday.
The 27-year-old was taken to a south London hospital with life-threatening injuries following the shooting on Consort Road, in Peckham, south London.
Police said at this stage there was no evidence the attack was targeted.
Detectives added that there was currently nothing to suggest the shooting victim had received any credible threats against her, and have appealed for witnesses.
They have not confirmed her identity.
Imarn Ayton, a friend of Ms Johnson’s, told the BBC doctors had carried out surgery on her fellow activist, which had gone well and she was “now with her parents”.
She said Ms Johnson had been at a party or gathering when she was injured but she did not believe “she was the intended victim”.
“As far as I am aware… this incident is more related to rival gangs as opposed to her activism,” Ms Ayton said.
Detectives from the Met’s Specialist Crime Command have been investigating at the scene and the surrounding area and are pursuing a number of lines of inquiry.
It is believed the shooting happened near a house where a party was taking place and a number of people may have been in the area, a Met Police statement said.
The Taking the Initiative Party said the attack followed “numerous death threats”.
Det Ch Insp Jimi Tele said: “This was a shocking incident that has left a young woman with very serious injuries. Our thoughts are with her family who are being provided with support at this terribly difficult time.”
He added: “If you saw anything suspicious in the Consort Road area in the early hours of Sunday morning, or if you have heard information since that could help detectives, it is crucial that you get in touch.”
Ms Johnson has been a leading figure in the Black Lives Matter movement in the UK and is a member of the Taking the Initiative Party’s leadership committee.
In its manifesto, the party describes itself as aiming “to create real change in communities across the UK by setting the agenda in government”.
It said it wanted to do this by putting forward “exceptional candidates who truly represent their communities, winning seats to create a Parliament that looks like the society it leads”.
In a statement on Instagram, the party said Ms Johnson was a mother of two and a “powerful voice” who had always been fighting for black people and against the injustices that affect the black community.
“Let’s all come together and pray for Sasha, pray for her recovery and show our support to her family and loved ones,” the statement said.
Black Lives Matters UK said it was shocked by the shooting of “a young mother and fearless political campaigner who was at the forefront of many BLM protests last summer”.
It said that while she was not part of the organisation, “she impressively founded a new Black-led political party and was dedicated to resist anti-Black racism”.
Announcing that a vigil would be held for her on Monday afternoon at King’s College Hospital, it added: “Any attempt to intimidate or silence her, is an attack on all of us.”