Alex Salmond and the ruling Labour group on Aberdeen City Council are embroiled in a new round of angry insults.

The First Minister accused Labour leaders of "insane...kamizaze" investment tactics which risked dragging the city into "total disrepute".

Labour, in turn, accused him of behaving like a bully, and of lying about a school visit during the recent Aberdeen Donside by-election

Mr Salmond criticised the city's ruling political group in two letters, one of which was sent to the authority's chief executive, Valerie Watts.

He was responding to a visit he made to a primary school and Scottish Government funding for a Piper Alpha memorial announced during the by-election campaign, which the SNP won. Ms Watts raised the issues with the SNP leader in June.

Mr Salmond wrote in reply: "I know as chief executive that you have to act on the instruction of your ruling group of councillors. However, I would ask you to reflect on this.

"I have been First Minister for over six years. During that time I have dealt with all 32 local authorities, of all political persuasions and none.

"No council behaves in the extreme manner of Aberdeen City Council over a range of issues.

"I would suggest that the majority group are now in danger of bringing the council into total disrepute with the knock-on reputational risks that that has for the great city of Aberdeen and its fine people."

Mr Salmond sought to justify an unplanned visit to Bramble Brae School in the city, which opposition councillors said was inappropriate.

He wrote: "The invitation by a member of the school's Parent Council was impromptu and my visit was not pre-planned....The visit was totally private. There was no press, media or party or Government officials and I was accompanied at all times by the class teacher and the Parent Council Member."

On the £100,000 funding for the Piper Alpha memorial, Mr Salmond said it was linked to the 25th anniversary of the offshore disaster.

"No human being that I know of, save apparently some members of Aberdeen council, would consider the government donation to the Piper Alpha Memorial Trust to be anything other than related to the 25th anniversary, not a by-election," he wrote.

The second letter accuses Labour councillor Angela Taylor of "totally bizarre" behaviour. She branded the First Minister a hypocrite for his stance against the refusal of some golf clubs to admit women members.

Mr Salmond, in his letter, said the councillor wants the Government to withdraw funding for the Scottish Open at Royal Aberdeen next year. He questioned why a city councillor would refuse wider investment he estimated at £10 million for the local economy.

"Even by the standards of a council which is becoming known for refusing key investment in the city, this would be a totally insane, indeed kamikaze, position," he wrote.

Barney Crockett, the Labour leader of the council, said: "These letters are an extraordinary intervention from a First Minister who is determined to bully anyone who doesn't agree with his view of the world.

"But what is worse is that he can't even tell the truth when he's put on the spot. Alex Salmond says his visit to Bramble Brae was 'impromptu', 'unplanned' and 'totally private'. If that was the case, why did the SNP press office issue a calling notice to the media inviting them to attend?

"Alex Salmond clearly is so used to telling different people different things that he can't even remember what the truth is any more.

"Alex Salmond is writing letters asking if councillors are taking 'insane' and 'kamikaze' positions. The best example of that sort of behaviour is the First Minister writing a letter which lies about his actions in abusing his position during a Parliamentary by-election.

"We know Alex Salmond will bully anyone, whether it's the BBC, journalists, newspapers, foreign politicians and now local councillors if they dare to speak out against him. But these letters are the latest and perhaps the worst examples of how low the First Minister will go in attempting to smear and attack those who disagree with him.

"Given that the First Minister has lied about the circumstances of his visit in his capacity as First Minister, I am demanding an apology and that he withdraws his inaccurate statement. With another lie, Alex Salmond has yet again demeaned the office that he holds."

Labour cited the SNP's media calling notice, which read:

You are invited to send a reporter and photographer and/or camera crew to:

WHEN: Monday 17th June, 14:30

WHERE: Outside Bramble Brae Primary School...

WHAT: First Minister Alex Salmond, Education Secretary Michael Russell and SNP Aberdeen Donside by-election candidate Mark McDonald will meet parents of pupils at Bramble Brae Primary School to hear their concerns over proposals by Aberdeen City Council's Labour-Tory administration to close their school. There is an opportunity for photographs and interviews.

Alex Johnstone, a Conservative North East MSP, said: "This letter is a thinly veiled threat and an appalling approach for the First Minister to take. The arrogance of the man knows no bounds.

"He is riding roughshod over the democratic process of Scotland by trying to assert his authority over Aberdeen City Council.

"This behaviour, and the manner of it, should leave us all fearing for the future of democracy in Scotland."