Unemployment in Scotland has increased to 223,000 in the past few months, meaning rates are above the UK average.
The rise, between April and June, was up by 34,000 on the same period last year, with the unemployment rate now at 8.4%, compared with 7.8% for the UK.
Scottish Secretary Michael Moore described the latest official figures as "disappointing", but said action was being taken to back economic recovery.
The figures came as the STUC warned of a "bleak outlook" for youth employment.
The Office for National Statistics data also showed the number of Scots in work went up by 8,000 over the previous three months, bringing the employment total to 2,444,000.
But Mr Moore said: "These disappointing figures are another undesirable reminder of the economic legacy this government has inherited and leaves us in no doubt about the challenges ahead.
"The government's measures to achieve our priorities of tackling the record deficit and achieving balanced economic growth for all parts of the UK will encourage the necessary investment to create new jobs."
STUC general secretary Grahame Smith said his organisation's own analysis of official figures showed the number of 18 to 24-year-olds claiming jobseeker's allowance for more than six months in Scotland had increased by 2,245 to 8,905 in the past year.
Criticising the UK government's decision to scrap the Future Jobs Fund, to help unemployed people back to work, he said: "These depressing figures confirm the outlook for the thousands of young people in Scotland currently looking for work is increasingly bleak, and there is nothing whatsoever in the policies of the coalition government to provide them with any comfort that the situation will improve any time soon."
The call was backed by Scottish Labour finance spokesman Andy Kerr, who added: "Defending jobs should be the government's first priority but the Tories' unnecessary cuts are causing longer dole queues."
Prime Minister David Cameron has promised a "light at the end of the tunnel" for the British economy following a programme of cuts he says is vital to reduce the country's spending deficit.
The UK government said it was also supporting Scottish businesses through plans for a "competitive" corporate tax system, an increase in the National Insurance contributions threshold and better access to finance.
Scottish Education Secretary Mike Russell said his government was investing in modern apprenticeships and a drive to help school leavers find jobs.
"The first increase in employment in Scotland for seven months is a sign of fragile recovery, and today's figures show that we are right to take comprehensive action to support jobs, skills and training," he said.