Millions of Washington Mutual customers woke up Friday morning fearing that their life savings, checking accounts and mortgages were in danger, after federal regulators seized the bank’s assets and sold them in a fire sale Thursday night.

Despite assurances by the federal government that it guarantees deposits of up to $100,000, customers descended upon bank branches to yank out their money on Friday, hoping it was still there.

At the Washington Mutual – or WaMu – branch in Forest Hills, N.Y., Bita Maharlouei was anxiously shuffling her feet as she waited for the ATM machine to display her balance. She was relieved to find every dollar where she had left it. “I almost had a heart attack,” she said.

Federal government regulators took over the failing financial institution late Thursday and quickly sold it to JP Morgan Chase for $1.9 billion. Now Chase is working to reassure its new customers that their assets are safe and sound.

“Customers should know and they should feel confident that their deposits are secured and safe," said Michael Fusco, a spokesman for the bank. "All their deposits have FDIC insurance. They should continue banking as they have and be assured that their bank is now backed by the strength and security of JP Morgan Chase.

Customers should continue to use the same checks, the same credit, ATM and debit cards and send their payments to the same addresses. Contact phone numbers, online services and web sites will also remain the same.

“We expect the re-branding and the systems integrations to be completed by the end of 2010,” Fusco said. He said customers will “learn well in advance of improvements, additional conveniences or any other changes that will happen to their accounts.”

Combined, there will be about 5,400 Chase and Washington Mutual branches in the country. About 10 percent of those will close as the bank streamlines operations.

Aida Gonzales came to her local WaMu branch to find out what arrangements she would need to make to keep her accounts and money safe.

She had been surprised to hear that her bank was in dire straits, and she was relieved to hear that Chase had taken over.

“I had no idea they were in a difficult financial situation," Gonzales said. "It was my understanding that it was on strong and solid ground. I have been surprised, as I suppose has everyone else throughout the city, the country and the world.”

Other customers were too anxious about their accounts to stop to be interviewed.

“I can’t. I have to check on my money,” said one man who declined an interview.

Leor Blumenthal came to WaMu two and a half years ago because it had better Internet tools than his local bank. He said he was worried that Chase won't keep the same policies and accessible tools that WaMu offered, like account minimums and ATM fees. “Whether I’ll stay with them I don’t know,” he said.

Mitchell Wimbish is also waiting to see what changes Chase makes before making up his mind. “I probably will stay unless things change that I can noticeably see,” he said.

Some WaMu customers who came to check on their money said they were not happy about becoming Chase customers.

Maria Nemec said she had been a Chase customer in the past and left the bank because of poor service. She doesn’t intend to stick around now. “I’m going to look around,” she said. She said she was concerned about losing her money and doesn’t trust the FDIC to come through if something goes wrong.

“I know it will take 99 years before you can get your money,” she said.