The Black Lives Matter activist Sasha Johnson is in a critical condition after sustaining a gunshot wound to her head in an incident in south London, her affiliated group, Taking the Initiative party, has announced on social media.

In a statement on the group’s Facebook page, the party said the incident happened in the early hours of Sunday and followed “numerous death threats”.

A Met police statement said there was nothing to suggest that it had been a targeted attack.

Taking the Initiative’s statement said: “It is with great sadness that we inform you that our own Sasha Johnson has sustained a gunshot wound to her head. She is currently hospitalised and in critical condition. The incident happened in the early hours of this morning, following numerous death threats.

“Sasha has always been actively fighting for black people and the injustices that surround the black community, as well as being both a member of BLM and a member of Taking the Initiative Party’s Executive Leadership Committee. Sasha is also a mother of 3 and a strong, powerful voice for our people and our community.”

Johnson is a prominent member of TTIP, which has been described as “Britain’s first Black-led political party”. She rose to prominence after last year’s BLM protests spread around the country, helping to organise marches and addressing crowds.

She has worked in activism and community support and achieved a first-class degree in social care at Oxford Brookes University.

Her page on the TTIP website said: “She has an immense passion for implementing change and justice and has been actively supporting the eradication of injustices in society by attending and leading protests.”

The TTIP has asked people to “all come together and pray for Sasha, pray for her recovery and show our support to her family and loved ones”.

Claudia Webbe, the MP for Leicester East, wrote online: “Shocking to hear of the gunshot to the head of Sasha Johnson; All women should be safe on our streets. Wishing her a full recovery. Sending love and solidarity to her family, friends and loved ones. There are still too many guns and violent weapons damaging too many lives #BLM.”

The Metropolitan police later reissued an appeal for witnesses in relation to a 27-year-old woman in hospital with life-threatening injuries after being shot in the early hours of Sunday.

The Met said the woman was found after officers were called to reports of gunshots in Peckham, south-east London, shortly before 3am.

It is believed the shooting occurred in the vicinity of a house where a party was taking place and a number of people may have been in the area.

A spokesperson said that, while the investigation was at an early stage, there was nothing to suggest it was a targeted attack or that the woman had received any credible threats against her before this incident. Detectives from the Met’s specialist crime command (Trident) were leading the investigation.

DCI 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 said detectives were making “good progress” in hunting the attackers but they needed help from the public and it was “crucial” that anyone who saw anything suspicious in the Consort Road area in the early hours of Sunday or who had heard information since then get in touch.

Tele added: “Finally, I recognise that this incident will have shocked those in the local community and further afield. I would ask people to avoid speculating as to the motive or the circumstances behind it.”

No arrests have so far been made.