WASHINGTON - Treasury Secretary Henry Paulson sought to reassure an anxious public Sunday that the banking system is sound, while also bracing people for more troubled times ahead.

"I think it's going to be months that we're working our way through this period - clearly months," he said.

Paulson said the number of troubled banks will increase as they struggle to cope with big losses on bad mortgages. The government this month took over IndyMac after a run led it to become the largest regulated thrift to fail.

"Of course the list is going to grow longer given the stresses we have in the marketplace, given the housing correction. But again, it's a safe banking system, a sound banking system. Our regulators are on top of it. This is a very manageable situation," he said in broadcast interviews.

Paulson used appearances on the Sunday talk shows to tell people that deposits up to $100,000 are fully insured. He said no one has lost a single penny on an insured deposit in the 75 years that the Federal Deposit Insurance Corporation has operated.

"We're going through a challenging time with our economy. This is a tough time. The three big issues we're facing right now are, first, the housing correction which is at the heart of the slowdown; secondly, turmoil of the capital markets; and thirdly, the high oil prices, which are going to prolong the slowdown," he said.

"But remember, our economy has got very strong long-term fundamentals, solid fundamentals. And you know, your policy-makers here, regulators, we're being very vigilant."

The secretary appeared on "Face the Nation" on CBS and "Late Edition" on CNN.