Iowa's largest public employees' pension fund confirmed Wednesday that hundreds of thousands of dollars in pension payments have been stolen from retirees' accounts and that state and federal law enforcement agencies have been asked to investigate.

The Iowa Public Employees' Retirement System, which serves employees of state and local governments and school districts, said in a statement that 103 retirees' accounts were compromised in mid-October. The system provides pension checks to 115,000 retirees who receive about $1.8 billion in payments annually.

The theft occurred when criminals who had obtained stolen Social Security numbers and birth dates used the information to register for IPERS' online account access and changed the direct deposit information. Then they redirected the pension payments to a different financial institution, said IPERS' spokeswoman Judy Akre. IPERS learned of the cybercrime on Tuesday.

IPERS has reissued the benefit payments to the correct financial institutions to ensure that all the affected retirees will receive their pensions, Akre said. Meanwhile, all retirees are asked to immediately confirm with their financial institution the receipt of their October payments, she said. In addition, online account access has been suspended.

"If you suspect something is wrong, contact IPERS as soon as possible," Akre said. However, the retirement system has run queries that indicate that the cyber-crime incident has only affected the 103 accounts, she added.

"The Department of Criminal Investigation and the FBI have been contacted and IPERS will pursue full prosecution against the criminals," Akre said. She didn't have a specific amount of money that was stolen, but she said it totaled in the hundreds of thousands of dollars.

Officials with the Federal Bureau of Investigation in Omaha and the Iowa Division of Criminal Investigation in Des Moines didn't immediately return calls seeking comment Wednesday.

Donna Mueller, IPERS' chief executive officer, said in an email that she is proud that the IPERS' staff quickly identified the affected accounts, isolated the problem and worked with banks to recover the money, and then reissued payments to the 103 retirees.

"This type of cyber-crime is happening more and more frequently," Mueller said. "We must all be vigilant in checking our bank statements, credit cards and other online financial accounts more frequently. If you suspect anything, call immediately."

State Treasurer Michael Fitzgerald, who serves on the IPERS' Investment Board, said Mueller advised him of the problem Tuesday and provided details of what had happened.

"Anytime our system is breached, I would say that this is a very serious concern. It has to be stopped," Fitzgerald said. "I give IPERS credit for catching this ...They have been able to make good on all the payments to people out there. But this has to be stopped or this great system that we have will just have to be changed."

Akre said that while the retiree accounts were compromised, IPERS' computer system was not hacked. IPERS has more than 350,000 members overall, including current and former public employees, and retirees. On June 30, the pension fund had assets of about $30.7 billion.

State Sen. Charles Schneider, R-West Des Moines, who co-chairs the Legislature's Public Retirement Systems Committee, said Wednesday night he's concerned that IPERS experienced a breakdown in its cyber-security system. He said he wants to know more information about exactly what happened to cause the breach.

"The point I want to make is that we will do whatever is necessary in order to make sure that we have the proper cyber-security measures in place and that Iowans' pension benefits are safe," Schneider said.

The problems experienced by IPERS come at a time cybercrime is a growing concern in government, business and other sectors. Iowa Secretary of State Paul Pate said in September he intends to ask the Iowa Legislature in 2018 for additional money for technology upgrades to the state's elections system to help ensure that election records remain secure against cyberintruders.

Pate said the integrity of the state's elections system remains intact, although he acknowledges it's been repeatedly attacked by outsiders who have included would-be hackers from Russia.