The Federal Reserve could continue full-speed ahead on its bond-buying program through the summer, but end it abruptly in the autumn if by then it is confident that the improvement in the jobs outlook is here to stay, a top Fed official said on Monday.

"We've seen good progress in the labor market outlook," Charles Evans, president of the Federal Reserve Bank of Chicago, told the CFA Society Chicago.

The Fed is currently buying $85 billion in Treasuries and mortgage-backed securities purchases each month in a bid to push down borrowing costs and spur growth. It has promised to continue the purchase until it sees a substantial improvement in the labor market outlook.

Improvement in the jobs situation since the program began already has some Fed officials calling for a reduction in the pace of purchases. The U.S. economy has added an average of 200,000 jobs each month for the last six months, and unemployment has fallen to 7.5 percent, down from 8.1 percent before the latest bond-buying program.

A few top Fed officials have urged the U.S. central bank to begin easing off the monetary gas pedal as soon as next month.

"Another approach, which doesn't get talked about that much, we could continue to go with $85 billion a month until we decide that absolutely we've seen enough improvement, and then bring it to a quick conclusion at that time," Evans told reporters after the speech.

"That would be a program going into the fall, I would think, because you can't really have that much confidence to bring it to an end" before that, he said. "I think at the moment the key issue is whether or not it is extremely likely that this (improvement) is going to be maintained over the next few months."

Evans, who is a voter on the Fed's policy-setting panel this year, is an influential voice at the central bank, which last year adopted his proposal to keep short-term rates near zero until unemployment falls to at least 6.5 percent as long as inflation remains in check.

When and how the Fed should bring to a close its third round of so-called quantitative easing, or QE3, is likely to be a topic of hot discussion when Fed policymakers next meet, on June 18-19.

Fed Chairman Ben Bernanke has sought to emphasize the Fed's flexibility with bond purchases, saying it could reduce or increase the pace of QE3 to adjust to economic needs.

On Monday, Evans said he believes the Fed does not necessarily need to wean the markets gradually of the bond-buying stimulus. But he said he is "open-minded" to the idea.

"I'm going to listen to my colleagues when we get together, whether it's the next meeting, or the meeting after, or the meeting in the fall," he said. "We have seen quite a bit of improvement."

The president of the San Francisco Fed, John Williams, said last week the Fed may be ready to start cutting back on bond buys this summer, as long as the jobs market continues to improve as he expects.

Evans suggested he would need "a little more time," to be sure on the labor market outlook, adding that he would prefer to see job gains of 200,000 "month after month" instead of on average, and overall economic growth gaining momentum.

Evans said he expects the economy to grow 2.5 percent this year and 3 to 4 percent next year, sticking to his forecast from the beginning of 2013 despite some softer economic data recently.

"I am confident that currently we have the appropriate monetary policy in place to support this economic growth so that we should build momentum through this year and it should become self-sustaining growth throughout 2014," he said.

Still, he emphasized, his forecast is not without risks.

"We continue to face powerful headwinds in the fiscal situation and the global economy," he said.

Evans reiterated his view that it is too early to get very concerned about too-low inflation, which has been running at about half the Fed's 2-percent target.

Inflation should rise back to the Fed's goal, he said, as the economy strengthens.

But if it is still low once unemployment reaches the 6.5 percent threshold the Fed has set for its low-rate policy, the central bank could easily keep rates low even longer.

Minneapolis Fed President Narayana Kocherlakota has called for the Fed to promise to keep rates low until unemployment reaches 5.5 percent, a full percentage lower than its current threshold, to give added thrust to the Fed's easy policy.

Evans said he was sympathetic to his colleague's view, but said he is not convinced that reducing the threshold further would provide more accommodation.