The statement followed a meeting of the bank's rate council which left the refinancing rate for the 17 European Union countries that use the euro unchanged at 0.5 percent. Draghi said the decision followed "an extensive discussion" of a potential rate cut.
Instead, in a marked departure of its usual stance of never pre-committing itself to targets, the bank offered an attempt at what is called "forward guidance". The practice - already used by the U.S. Federal Reserve - is designed to give more clarity about how long a central bank will continue its measures to stimulate the economy.
Also Thursday after its monthly policy setting meeting, the Bank of England issued its own form of forward guidance. In his first policy since taking over the bank, new governor Mark Carney issued a statement saying that expectations of a rate rise "was not warranted".
Markets reacted dramatically on the banks' statements. In London, the FTSE 100 index of leading shares was up 3 percent, while Germany's DAX stock index was up 2.16 percent. Meanwhile, the pound and the euro fell against the dollar.
At his news conference following the ECB meeting, Draghi rebuffed attempts by journalists to pin him down about what an extended period meant. Asked if it meant 6 or 12 months, he said, "an extended period of time is an extended period of time."
He did not specify any concrete targets for unemployment or growth, as the U.S. Fed has done. The U.S. central bank has said its rates will remain near zero until U.S. unemployment falls to 6.5 percent.
The ECB provided additional guidance by saying that rates would remain low so long as three conditions continued to exist: no threat of inflation, weak economic output, and anemic lending by banks. But again, no figures were mentioned.
Still, Draghi was clearly at pains to show the bank as leaning toward doing more to help stimulate the eurozone. The region's economy shrank 0.2 percent in the first quarter, the sixth quarterly decline in a row.
The eurozone economy has lagged due to the government debt crisis which has forced countries to cut back on spending and raise taxes to try to reduce levels of debt. Growth is key to getting the eurozone out of its problems. An expanding economy increases government tax revenue as people and businesses earn more. And it reduces the size of debt relative to the size of the economy.
The ECB president said the current record low benchmark rate of 0.5 percent "is not the lower bound" and added that the bank's statements were intended "to inject a downward bias in interest rates for the foreseeable future."
In theory, a low interest rate could stimulate the economy by reducing borrowing costs on the loans businesses need to expand and create more jobs.
Yet the currently low refinancing rate - the rate the ECB charges private sector banks to borrow - is not being passed on by banks. That is because banks themselves often have strained finances and are keeping money back to meet new regulatory requirements aimed at strengthening the financial system.
So there is skepticism among economists and ECB leaders themselves about how much good another rate cut will do. Instead, much attention has focused on tools the ECB could use beside rate cuts to try to get the economy going again.
The bank has also said it is looking at ways to promote lending to small companies, working in cooperation with other EU institutions. However the ECB cannot do that alone. Steps to free up more money for banks to lend - by encouraging them to bundle small business loans into securities which could then be sold off - would take months to set up.
The bank has already cut interest rates, made cheap three-year loans to banks, and offered to buy the government bonds of indebted countries in the open market if they promise to reform their finances. It has also given one form of specific guidance, saying its regular short term loan offerings to banks will give as much as the banks want to take through the middle of next year.