NAPLES, Italy — European Central Bank head Mario Draghi underlined the bank’s willingness to ramp up its stimulus efforts with large-scale bond purchases if needed – but otherwise offered no new economic help at the bank’s meeting Thursday.

Draghi called the economic recovery in the 18 euro countries “weak, fragile, and uneven.”

Even so, he offered no new help, choosing instead to stress what the bank has already done, and repeated previous statements about the bank’s willingness to do more.

At a news conference after the ECB’s decision to keep interest rates on hold, Draghi said the ECB will launch its already-announced program to buy bonds made of bundles of bank loans later this year. The purchases are meant to encourage banks to lend more.

Draghi said the program would have a “sizeable impact on our balance sheet,” which measures how much the bank is doing to support the economy. Draghi has said he wants to push the balance sheet toward levels it had in 2012, which would imply $1.26 trillion in new stimulus.

Draghi added that the bank is ready, if needed, to step up its bond purchases – a step that would pour newly printed money into the financial system.

He noted recent data confirms the weakening of growth in the 18 countries that use the euro. The eurozone did not grow at all in the second quarter.

He noted that “we’ve decided a massive amount of measures now,” and indicated the bank wants to see how well they work.

Markets seemed to think Draghi had offered less than hoped. The euro rose to $1.2670 from $1.2630 before Draghi’s comments, a sign currency traders expect less rather than more future stimulus. And stocks are down across Europe.

The ECB has since June cut its benchmark refinancing rate to a record low and offered cheap, long-term loans to banks tied to their lending to the real economy. The first such loan offer, however, got fewer takers than market analysts expected when banks drew only 82.6 billion euros. The ECB says the uptake can only be measured together with another offering in December.

All the ECB measures are aimed at making credit cheaper and more abundant for companies, in hopes they will borrow, expand and hire.

Street protests outside the ECB meeting building in Naples turned violent. Riot police used water cannons to break up more than 3,000 demonstrators carrying banners against government austerity policies and unemployment.

Speculation that the ECB may make wider purchases to include government bonds has weighed on the euro, driving it down from $1.39 in early May. So far, that has been one of the most significant effects of the ECB’s record low interest rates and loose monetary policy. The lower euro helps raise inflation. And it helps exporters by making their goods cheaper in foreign markets.