BEIJING (Reuters) - Three of China's major state banks said on Thursday they will start to lower interest rates on existing mortgages for first-home loans.

The move is one of several support measures flagged by Beijing in recent weeks for the country's crisis-ridden property sector amid mounting concerns over the health of the world's second-largest economy.

Interest rates on existing first-home loans will be cut to the level in place when a home was purchased, the Industrial and Commercial Bank of China Ltd (ICBC), Agricultural Bank of China (OTC:ACGBF) and Bank of China Ltd (BOC) said in statements.

The reduction will come into effect on Sept. 25, they said.

China's home loans totalled 38.6 trillion yuan ($5.3 trillion) at the end of June, representing 17% of banks' total loan books.

($1 = 7.3232 Chinese yuan)