Alex Salmond has challenged Prime Minister David Cameron to “level” with the people of Scotland and answer three questions about his offer for more powers in return for rejecting independence.
The Scottish First Minister used a speech at St Andrews, Fife, to ask for more detail 24 hours after Mr Cameron set out his defence of the UK in Edinburgh.
Mr Cameron, while urging voters to say "no" in the referendum in 2014, held out the prospect of enhanced devolution - but offered no details about what those powers could be.
Mr Salmond, who has already complained that Scots have been "fooled" by Conservatives before, said the UK Government could start by making changes to the current Scotland Bill, which aims to transfer some tax and financial responsibility to Holyrood.
The First Minister said: "It is possible, because times change, that David Cameron's offer to Scotland is a genuine one.
"But at the very least it raises three major questions.
"If the offer is genuine, will the final version of the Scotland Bill contain provisions for further economic powers that have been asked for by the Scottish Parliament over these last nine months?
"Secondly, if the offer is genuine, why does the Scotland Bill contain proposals to transfer some powers back to Westminster?
"And thirdly, if the Prime Minister's offer is genuine, will he set out the full proposals by the end of the Scottish Government's referendum consultation in May, so the Scottish Government - and far more importantly, the Scottish people - can develop an informed view about what might be on offer?"
Mr Salmond, addressing the Convention of Scottish Local Authorities conference, said he accepts he must set out the "detailed prospectus" for independence.
But he added: "The Prime Minister can't get away with anything less. It's time to level with the people of Scotland."
Mr Salmond met the Prime Minister yesterday to discuss the staging of the referendum, which the Scottish Government wants to hold in autumn 2014.
The SNP leader has also held open the door to allowing a second question on the ballot paper, offering maximum devolution short of independence - so-called "devo max".
But Mr Salmond's critics have called this a fall-back in the event of a "no" vote and that it could muddy the waters.
The talks in Edinburgh followed a set-piece speech by Mr Cameron, the Tory leader, who said devolution could be built upon once it is decided whether Scotland stays in political union.
Mr Cameron, in his speech, said: "When the referendum on independence is over, I am open to looking at how the devolved settlement can be improved further.
"And, yes, that does mean considering what further powers could be devolved.
"But that must be a question for after the referendum, when Scotland has made its choice about the fundamental question of independence or for the United Kingdom."
The UK Government has called for the straight question to be held "sooner rather than later", with late 2013 given as an option.
There is further disagreement on whether to allow voters as young as 16 to take part.
After Mr Cameron's new offer to consider more powers, Mr Salmond immediately demanded details, asking: "Where's the beef?"
He recalled the run-up to the 1979 devolution referendum when MP Sir Alec Douglas-Home said a Tory government would introduce a better deal.
Mr Salmond added: "Scotland, I don't believe, will be fooled twice."