HSBC Bank USA said Friday that its core banking system was back in full operation, after a system crash dating to the prior weekend snarled the posting of transactions to customer accounts for much of last week.

The bank, a unit of HSBC Holdings PLC of London, would not profide details on the extent of the problems, but news coverage of the issue appeared to be concentrated in upstate New York, in the market of the former Marine Midland Bank, where HSBC first invested in 1980.

Among other things, the system problems interfered with customer access to their accounts online, blocked some large withdrawals from automated teller machines, and delayed the direct deposit of payroll by more than a day for as many as 8,000 employees of Catholic Health System and a number of University at Buffalo employees, according to the Buffalo News.

An HSBC spokeswoman would neither discuss the nature of the problem nor provide an executive to do so.

In a statement, the bank described the problem as a "systems issue which impacted our ability to process customer transactions."

Customers' funds were always secure, the banking company said. "While most all of the impacted systems are now up and running, we are still working through the remaining recovery efforts."