Scottish Government minister Christina McKelvie has died at the age of 57, her partner has announced.

Ms McKelvie took leave from her role as alcohol and drugs minister last year to seek treatment for secondary breast cancer.

On Thursday, SNP MSP Keith Brown, Ms McKelvie's long-time partner, announced she had died this morning.

"To us, she was our beloved mum, partner and gran to Maeve and Leo," the statement said.

"She was always hard working and enthusiastic and lit up every room she was in with her positivity and bright smile.

"She was always proud of her working class roots in Easterhouse and often said she could not have dreamt of becoming a government minister for the Scottish Government."

The flags at Holyrood will fly at half mast in honour of Christina McKelvie, the Presiding Officer has said.

In a statement released on Thursday, Alison Johnstone expressed her "most sincere condolences" to Ms McKelvie's family, adding that she was "deeply saddened" by her death.

"A passionate campaigner and an engaging parliamentarian, Christina served as a committee convener and as a minister under three first ministers. I remember Christina's warm welcome when I arrived as a newly-elected MSP in 2011.

"Christina sponsored the Wear It Pink campaign in Parliament for many years, and said how privileged she felt to be able to use her platform as an MSP to boost the work of others."

Scotland's First Minister John Swinney has said the SNP has "lost one of its finest". He said: "I am devastated to learn of the passing of Christina McKelvie, one of the kindest and most generous people I have ever met in my life.

"In all the years since I first met Christina, I have been so grateful to call her my friend and colleague and to benefit from her warmth and loyalty.

"Christina was fiercely proud of her Easterhouse roots, and she often spoke of how injustices her family experienced in her childhood had inspired her to join the trade union movement and enter elected politics."

He said Ms McKelvie acted on her values in her almost two decades at Holyrood and was a "fierce champion for equality, social justice, for Scottish independence and for a better world".

He said his "thoughts and prayers" are with her family and friends and added: "The Scottish National Party has lost one of its finest, and I have lost an outstanding minister in my government."

Former first minister Nicola Sturgeon has paid tribute to her "beautiful friend".

In a post on Instagram, Ms Sturgeon said: "It is going to take a very long time for those of us who love her to come to terms with the passing this morning of our friend and colleague Christina McKelvie MSP.

"Christina was kind, loyal, compassionate and full of life.

"As a politician, her ability to connect with people on a very human level and and understand instinctively the challenges they were facing was her superpower.

"She had the biggest heart of anyone I have ever known. I will never forget the friendship and kindness she showed me over many years."

Ms Sturgeon expressed her condolences to her partner and SNP depute leader Keith Brown, adding: "RIP my beautiful friend."