China's holdings fell by $24 billion to $843.7 billion, a decline of 2.7 percent, the Treasury Department said Monday in a monthly report on debt holdings.

Total foreign holdings of Treasury securities rose $45.6 billion to a total of $4 trillion, an increase of 1.2 percent.

The debt figures are being closely watched at a time when the U.S. government is running up record annual deficits. A drop in foreign demand would lead to higher interest rates in the United States. The yield on Treasuries rises when fewer people invest in them.

It would start with the U.S. government paying more interest on its $13.3 trillion national debt and then ripple through the economy. Consumer loans such as home mortgages and auto loans track the yields on Treasurys, so they could rise, too.

So far, interest rates in the United States have remained extremely low. A weak economy has depressed borrowing by the private sector and the Federal Reserve has kept a key interest rate at a record low level of zero to 0.25 percent in an effort to spur stronger growth.

U.S. interest rates have also been kept low by the European debt crisis in the spring. That triggered more investment in U.S. Treasurys, which are considered the safest investment in the world because the U.S. government has never defaulted on its obligations.

China is the largest foreign holder of Treasury securities. The $24 billion decline in China's holdings in June followed a $32.5 billion drop in May. China's holdings had hit a high for this year of $900.2 billion in April.

Japan, the second largest foreign owner of Treasury bonds, increased its holdings in June to $803.6 billion. That's an increase of $16.9 billion or 2.5 percent. Britain's holdings rose 3.5 percent to $362.2 billion.

Japan had for years been the No. 1 holder of Treasury securities, but was overtaken by China in September 2008.

New government data showed that Japan lost its place as the world's second largest economy in the second quarter of this year. China moved up from No. 3 to the No. 2 spot, behind the United States.

While the data on total economic output was for the second quarter, analysts believe China is on track to surpass Japan for the entire year and become the world's second largest economy.

The Treasury report said that net purchases of long-term securities, a category that covers not only U.S. government debt but also debt of U.S. companies, increased by $44.4 billion in June after rising $35.3 billion in May.