European Central Bank chief Mario Draghi played down concerns over softness in the euro zone economy yesterday as the ECB kept policy on hold, bolstering expectations that it will halt bond purchases by year-end.

Draghi argued that the 19-country currency bloc's economy remained strong but acknowledged evidence of a "pull-back" from exceptional growth readings seen around the turn of the year.

"Overall, however, growth is expected to remain solid and broad-based," he told a news conference after ECB policymakers held their meeting.

Draghi said risks related to the threat of protectionism had become "more prominent" but stressed the bank was confident that it was on the right track towards gradually weaning the economy off an unprecedented period of stimulus.

"The bottom line is ... caution in reading these developments, caution tempered by an unchanged confidence in convergence of inflation to our inflation aim," he said. The ECB targets inflation of below but close to 2 percent.

With yesterday's decision, the ECB's bond purchases, aimed at stimulating growth and inflation through rock-bottom debt costs, will continue at 30 billion euros a month at least until the end of September, or beyond if needed to prop up inflation. The deposit rate, currently the bank's primary interest rate tool, will remain at -0.40 percent. The main refinancing rate will stay at 0.00 percent.