Firms in the United States added 290,000 jobs in April, the most in four years, dpa quoted the Labour Department as saying today. The data is considered a strong sign that the job market has begun recovering from last year's damaging recession. But the unemployment rate climbed to 9.9 per cent, from 9.7 per cent in the first three months of 2010, as more than 800,000 people who had given up looking for work re-entered the labour market. The monthly gains were mostly in the private sector as companies began hiring in manufacturing, health care, professional and business services, among others. More than 60,000 workers were also hired temporarily for the census, a population count conducted by the government every 10 years. Since the start of the year, the US economy has now gained 573,000 jobs - 483,000 in the private sector - as companies are becoming more encouraged that the US recovery is sustainable. "In the private sector, we're starting to see growth in a broader scale," Labour Secretary Hilda Solis told Bloomberg Television. "We still have work to do." Major US stock indices fell 0.5 per cent within minutes of trading opening in New York, as the employment gains were overshadowed by the Greek debt crisis and possible trading errors that caused massive market swings on Thursday. The April jobs figures were better than most economists expected, while the Labour Department also revised upwards its job gains for the previous two months by 121,000. The economy added 39,000 jobs in February, revised up from a 14,000 loss, and gained 230,000 jobs in March, revised from 162,000, the department said. But the climb in the jobless rate to 9.9 per cent surprised analysts and came as the size of the labour force surged by 805,000 people.