FRANKFURT—Top European Central Bank officials escalated a dispute with Berlin over the ECB’s easy-money policies on Monday, warning that Germany itself is partly to blame for the ultralow interest rates that are harming savers and pensioners.

In a speech to Asian government officials and business leaders, ECB President Mario Draghi said low interest rates were merely a symptom of an underlying economic problem—the compression of investment returns globally due to an excess of savings.

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