The combined output of manufacturing and service industries further deteriorated last month across the debt-strapped eurozone, reinforcing growing fear that the region is on the brink of another recession.
The composite purchasing managers' index (PMI), a measure of private-sector activity based on surveys of 4,500 firms, slumped to 46.7 in April from 49.1 in March, according to Markit Economics.
Economists were expecting no change from the preliminary April reading of 47.4.
Markit said that its April services PMI for the euro area fell to 46.9 from 49.2 in March and came in below the preliminary estimate of 47.9.
A reading of less than 50 signals a contraction in activity.
The composite PMI data suggests that the eurozone is on track to see GDP shrink by 0.5% in the second quarter, said Chris Williamson, chief economist at Markit.
"Business and consumer confidence appears to have deteriorated markedly across the region since the uplift seen at the start of the year, suggesting that stimulus measures implemented by the ECB have not had a lasting impact on the real economy," he said.
The results of the survey of manufacturing firms released on Wednesday showed that activity in that sector touched the weakest level since June 2009.
Economic contraction in the eurozone that began in the final three months of last year, likely persisted in the first quarter of this year, and has continued into the second quarter, according to most economists.
The euro-zone economy shrank by 0.3% in the fourth quarter of last year.