A Scottish Tory member who joked about Nicola Sturgeon's miscarriage should be expelled from the party, the SNP has said.

Jane Lax, Moray Conservatives' association treasurer, resigned from her post and was suspended from the Tories on Wednesday over the "unacceptable" online comments.

She is now facing a formal disciplinary investigation into the incident.

Responding to a Twitter user who suggested the First Minister's miscarriage was "fictional", Ms Lax replied: "Is that when she dropped a book?"

Sturgeon revealed she had lost a baby in 2011 at the age of 40, back when she was deputy first minister.

Speaking in 2016, she said she had wanted to bring her "painful experience" out into the open to challenge the assumptions some people make about women in politics who don't have children.

A spokesman for the Moray SNP said local party members were "appalled by the personal and deeply offensive comments made against Nicola Sturgeon".

He added: "In public life, politicians can expect criticism around policy-making decisions but these comments go much further.

"To poke 'fun' at a deeply personal and traumatic event in the First Minister's private life represents a new low for the Conservatives in Moray.

"It calls into question the processes which allow someone with such extreme views to hold office in the Moray Conservative party.

"We look forward to a full public apology from and appropriate sanction against Jane Lax."

A senior source within the SNP went further, demanding Ms Lax's full expulsion from Ruth Davidson's party.

"Ms Lax should be expelled from the Scottish Tories," they said.

"And if action isn't taken against her, given the vile nature of her comment, it will allow everyone to see what kind of party they are.

"Ruth Davidson has been keen to highlight social media abuse but if she fails to condemn this it will expose her hypocrisy for all to see."

A spokesman for the Scottish Conservatives said: "These comments were completely unacceptable.

"As a result, Jane Lax has been suspended by the party pending a disciplinary procedure, and has resigned as treasurer of the Moray association."

The incident comes only a day after the First Minister told a Fringe event that some of the online abuse she receives "would make your hair curl".

She said: "It's horrible, misogynist, really filthy stuff, and women across all parties get that, so we should always call that out.

"I don't spend any time looking at that stuff."

Ms Lax has been pictured on social media campaigning with the party, including with Moray MP Douglas Ross.

She also featured as a questioner in the audience of an episode of BBC's Question Time in Elgin in April.

In August, she posed with Conservative MP for Banff and Buchan, David Duguid, who described her on Twitter as a "@bbcquestiontime legend".