* Global markets fall on credit jitters

* Bernanke sees risks for U.S. economy

* General Motors fall after halting dividend

* Freddie Mac, Fannie Mae slide anew (Updates to midmorning)

By Ellis Mnyandu

NEW YORK, July 15 (Reuters) - U.S. stocks slid on Tuesday, led lower by financial shares after Federal Reserve Chairman Ben Bernanke said a weakening housing market, tighter credit and rising oil prices threaten the economy.

World stock markets were already nervous about the credit crisis' impact on the financial sector and economic growth before Bernanke's comments to the Senate Banking Committee.

Shares of Bank of America (BAC.N: Quote, Profile, Research), the No. 2 U.S. bank, fell more than 5 percent at $19.03, and insurer American International Group (AIG.N: Quote, Profile, Research), declined 9.5 percent to $20.41.

Financial markets and institutions remain under "considerable stress," but restoring stability is a top priority for the U.S. central bank, Bernanke said.