China bought more U.S. Treasury debt in September and total foreign holdings rose for a second straight month.

The Treasury Department says total foreign holdings of Treasury debt increased 1.9 percent to $4.66 trillion. China, the largest foreign holder, bought 1 percent more to bring its total holdings to $1.15 trillion. China cut its purchases 3.1 percent in August.

The gains suggest foreign demand for U.S. debt remains strong, despite a prolonged debate this summer over increasing the nation's borrowing limit. Investors also don't appear to be concerned that Standard & Poor's downgraded the credit rating on long-term U.S. debt.

S&P said it lowered the U.S. credit rating because of politics that slowed the debt limit increase and not because it thought the U.S. couldn't pay its bills.