UK unemployment rose by 70,000 to 2.56 million between December and February, the Office for National Statistics (ONS) has said.
It pushed the unemployment rate to 7.9%, raising further questions about the UK's economic strength.
The number of people in employment also fell, while earnings growth slowed considerably, according to ONS data.
But there was positive news on the number claiming Jobseeker's Allowance last month, down 7,000 to 1.53 million.
'Challenges ahead'
The number of people in work fell by 2,000 in the latest quarter to February, to just under 30 million, the first time the figure has dipped since autumn 2011.
And the ONS said that average regular pay, excluding bonuses, rose by 1%, the lowest since records began more than a decade ago.
The news hit sterling, with the pound falling more than a cent against the dollar on concerns that a weaker labour market pointed to worsening economic prospects.
It was up against the euro as the equity markets in London closed, having reversed earlier losses.
Employment Minister Mark Hoban acknowledged that there were "still tough challenges ahead", but highlighted the importance of the fall in the number of people claiming
Jobseeker's Allowance (JA), and especially the drop among young people.
"We will continue to give jobseekers all the help and support they need to realise their aspirations," he said.
Ministers said the number of JA claimants fell in every region of England, Wales and Scotland, while the number of new claims was at its lowest level for more than four years.
The number of young people claiming JA is down by 2,800 on the month, and is 65,400 lower than last year.
However, the ONS data also revealed that 900,000 people have been out of work for more than a year, an 8,000 increase on the three months to November, while the number of unemployed 16 to 24-year-olds rose by 20,000 to 979,000.
Despite the