Key US employment figures disappointed on Friday, with just 151,000 jobs being created in August.
The non-farm payroll number came in below analysts’ expectations, many of whom had expected around 190,000. It also falls well below the average monthly rise of 204,000 this year.
The unemployment rate remained flat at 4.9 percent, unchanged from July.
The figures are a key piece of data for the Federal Reserve who are currently deciding when to raise interest rates, and are likely to negate a September rate rise. However, several Fed members have hinted that a change will be made this month, with Yellen herself stating that “the case for an increase in the federal funds rate has strengthened in recent months”.