The president of one of Japan's major financial groups has apologized again for systems failures that shut down ATMs across the country. He said the problems have been fixed and the machines are more secure.

Mizuho Financial Group President Sakai Tatsufumi said, "I would like to apologize deeply from the bottom of my heart. We aim to drastically strengthen our crisis management system and enhance our organizational strength."

In the worst incident -- in late February -- 80 percent of Mizuho Bank's ATMs were affected nationwide.

Customers were unable to withdraw cash. And in some cases, the machines swallowed their cards and bankbooks.

Mizuho says it has made changes that will stop its ATMs from eating cards and bankbooks if the system goes down again.

It also says it will respond more quickly to future systems failures, and send out employees to check affected ATMs as soon as possible.