HM Naval Base Clyde is the home of the Trident missile system

He has written to representatives of 189 countries signed up to the Nuclear Non-Proliferation Treaty (NPT).

Mr Salmond is asking them to back his bid for Scotland to have observer status at future treaty talks.

Labour MP Eric Joyce said the letter could "potentially damage our national security interests".

Nuclear weapons

Defence is not an area devolved to Holyrood.

Mr Joyce, the MP for Falkirk, said that the UK had very complex relationships with some countries such as Iran and Zimbabwe.

Mr Joyce said: "Alex Salmond simply cannot know whether he is making damaging assertions or not because he does not know the nature of our relationships with many of these complex and difficult countries.

"He has written to some very despotic and dangerous individuals, which we have very sensitive and complex relationships with, and treated it like a weekly political football. It is potentially very damaging to our national security."

I really do think it is the wrong thing for the SNP to be doing to be hosting a conference they don't have responsibility for Wendy Alexander Scottish Labour leader Read Brian Taylor's blog

Britain's Trident nuclear submarine fleet is based at HMNB Clyde at Faslane.

The SNP government is opposed to the renewal of the nuclear weapons system.

Deputy First Minister Nicola Sturgeon said Iran and Zimbabwe were written to, along with other countries, because they are signatories to the Nuclear Non-Proliferation Treaty.

"It is not about trying to make common cause with any particular country.

"Given that Trident is based in Scotland, I think it is right that we make sure all of these countries know Scotland's view," she said.

Ms Sturgeon, who is hosting an anti-Trident summit organised by the Scottish Government, added that a majority of Scottish MPs and MSPs and the public were opposed to replacing the Trident system.

Constitutional matters

The topics to be discussed will include how devolved powers could be used to block the possible replacement of the nuclear missile system.

Opposition parties said the event proved that the SNP focused on constitutional matters more than health and education.

Scottish Labour leader Wendy Alexander said the government was wrong to host the event.

She told BBC Scotland's Politics Show: "There are strong views on either side of the argument.

"But it is not a Scotland-England issue, and I really do think it is the wrong thing for the SNP to be doing to be hosting a conference they don't have responsibility for."