The Scottish Conservative interim leader has denied he sacked Ross Thomson as an election candidate for Aberdeen South over groping allegations.

Jackson Carlaw said Thomson's decision to abruptly end his re-election campaign was "taken entirely on his own account" amid fresh claims against him by Labour MP Paul Sweeney.

The Scottish Tory chief said he supported Thomson's decision but that he had "absolutely not" forced him to drop out.

He also confirmed the party itself has not investigated any of the allegations.

Sweeney told a Sunday newspaper Thomson had "groped" him and tried to put his hands down the front of his trousers in Westminster's Strangers bar last October.

He said he had referred the alleged incident to the House of Commons' parliamentary commissioner for standards but went public over fears the matter would not be dealt with before the December 12 general election.

In February, Thomson was escorted from Strangers bar by police after reports of "sexual touching".

The Aberdeen South MP had officially launched his re-election campaign on Saturday, and in his initial response to Sweeney's allegations he vowed to fight on, branding the claims "politically-motivated smears".

But by Sunday afternoon, Thomson announced he would not be standing as the Tory candidate on December 12, which he called "the most difficult decision that I could ever make".

He has now been replaced as Aberdeen South candidate for the Tories by Aberdeen City Council co-leader Douglas Lumsden

Speaking at a campaign event in Hamilton, Carlaw said: "I've known Ross for many years.

"This is a decision he's taken entirely on his own account and I support him in the decision and the conclusion he's come to.

"The campaign will go forward. We've selected a new candidate in Aberdeen South now and I'm confident we'll take the fight to the SNP in that seat and hold it."

Asked by STV's political editor Colin Mackay if he had sacked Thomson, the interim party leader responded: "Absolutely not."

Further pressed on if he had personally ordered a Tory investigation into the claims, Carlaw said he had not received any complaints and that it was a matter for the Commons authorities.

He added: "It's yet to actually report - we've not heard the findings from the House of Commons yet.

"However, Ross has said that he thinks the appropriate thing for him to do now is to stand aside."

Scottish Labour leader Richard Leonard said the alleged incident showed the need to "clean up" behaviour in politics.

Campaigning in Airdrie on Monday, he told STV News: "When there are serious allegations made then action needs to be taken and firm action needs to be taken.

"I don't know the ins and outs of this particular case but there is no doubt that in politics that we need to clean things up.

"We need to make sure that standards of behaviour are set at a much higher level than clearly they have been."

First Minister Nicola Sturgeon said Thomson had made the right decision.

On the campaign trail in Rutherglen, she said: "It couldn't have been easy for the MP who made those allegations to come forward and do so.

"I don't know the veracity of the allegations. It's not for me to sit in judgment.

"There are investigations, as I understand it, under way but I think in all the circumstances it's probably for the best that he is not a candidate in this election."

Thomson has said he will continue to fight to clear his name and claimed "defamatory" allegations against him had made his "life a living hell".

A spokesman for Sweeney said on Sunday: "In light of the failure of the parliamentary commissioner for standards to resolve this matter before the general election, Mr Sweeney feels it is important that voters in Thomson's constituency should be aware of his behaviour as their representative at Westminster."