Scotland will continue to play a key role in the defence of the UK, the Prime Minister has insisted.
Despite slimmed-down plans to increase the number of service personnel north of the border, David Cameron highlighted "Scotland's continued vital role in our defence".
The number of military personnel in Scotland will still increase to its highest level since 2007, the Prime Minister said.
The Conservative leader hit back at claims from Scottish First Minister Alex Salmond that the UK Government had broken its commitment to the people of Scotland.
At the same time, Downing Street said Scots deserved to know what military capability the country would have if it left the UK and became independent.
A Downing Street spokesman said: "We have yet to see credible projections, including any put forward by the Scottish Government, which would maintain a military presence in an independent Scotland on the same scale as the plans we have set out.
"People in Scotland deserve to know what military capabilities they would plan for an independent Scotland and how these could be afforded on the proposed budget of around 7% of what the UK spends on defence and security."
Meanwhile, in a letter to Mr Salmond, the Prime Minister said it was "important for the referendum debate for people to understand that the outcome you seek for Scotland is the end of centuries of our shared British military effort, and the footprint of this military capability in Scotland".
That came in reply to a strongly-worded letter from Scottish National Party (SNP) leader Mr Salmond in which he claimed the UK Government's bond of trust with Scots had been damaged by the slimming-down of plans to increase soldier numbers north of the border.
Defence Secretary Philip Hammond announced last week the number of Armed Forces personnel in Scotland will increase by about 600, far fewer than was promised two years ago. The then defence secretary Liam Fox had pledged in 2011 that the size of the Army in Scotland would increase from about 3,500 to 8,500.
