Prosecutors said Friday they have raided the main branch of Nonghyup Bank as part of their ongoing investigation into allegations that the country's fourth-largest lender extended illegal loans.

Nonghyup Bank is under suspicion of granting unauthorized loans to Resom Resort, although the resort group has experienced financial difficulties for about 10 years.

The Seoul Central Prosecutors' Office confiscated accounting books, internal documents and computer hard disks at the bank's main branch located in central Seoul.

Prosecutors raided the headquarters of Resom Resort earlier this week, alleging the resort's board members embezzled company funds.