In prepared remarks, Powell said that the Federal Reserve stands ready to "act as appropriate" to sustain a decade-long expansion.

He said US economic growth was being weighed down by a considerable set of risks - including persistently weak inflation, slower growth in other major economies, and a downturn in business investment driven by uncertainty over global trade tensions.

German government bond yields fell around 3 basis points after the speech to -0.315pc and closed the day at around -0.31pc having hit a 10-day high of -0.279pc earlier in the session after better than expected French industrial production data.

Other euro zone bond yields also came off their day's high.

Investors sold German Bunds aggressively after the French industrial output data. That pushed Germany's 10-year bund yield up seven basis points to -0.279pc, its biggest one-day move since June 2018.

Analysts attributed the move partly to the French data. French industrial output rose 2.1pc in May, its biggest monthly increase since November 2016.

"There were good numbers in France this morning, so there's some return to risk appetite," said Jean-Christophe Machado, rates strategist at Natixis. "But the reaction is a bit extreme ...Bunds are expensive ... maybe there's some profit taking ahead of the Fed."

In a sign that investors are showing frustration with the super low yields on offer, a German 10-year Bund sale failed to drum up enough demand to cover the targeted 4 billion euro deal size.

Germany's debt management office sold 3.155 billion euros of 0.00pc 10-year Bunds, holding on to 845 million euros.

Markets on Friday scaled back expectations of deep rate cuts by the Fed after better-than-expected US jobs data.

Markets are now pricing in a 25-basis-point cut at the Federal Open Market Committee's next session on July 30-31. But the potential for disappointment is high, said Christian Lenk, rates strategist at DZ Bank.

"It will be pretty hard for Powell to meet all the expectations that are in the market," he said. "If you look at the fundamentals, the situation in the US is not that bad that would justify a long series of rate cuts."

In a Q&A session on Twitter on Tuesday, the European Central Bank's chief economist, Philip Lane, reiterated that the ECB has the tools it needs to keep inflation on track towards its goal of just under 2 percent.

Risk appetite may also grow after US and Chinese trade officials held a "constructive" phone conversation on Tuesday, according to White House economic adviser Larry Kudlow, marking a new round of talks after the world's two largest economies agreed to a truce in a year-long trade war.

Italy on Tuesday sold a 50-year bond with more than 80pc of demand coming from foreign investors, led by Germany, the head of its debt management office told Reuters.