WASHINGTON — The Federal Reserve, seeking to combat the effects of a serious credit crisis, said Tuesday it had auctioned $30 billion in funds to commercial banks at an interest rate of 3.010 percent.

It marked the fifth in a series of auctions that so far have pumped $130 billion in money into the nation's banking system in an effort to provide cash-strapped banks with extra reserves. The Fed's hope is that the increased resources will keep banks lending and prevent a severe credit squeeze from making the current economic slowdown worse.