BEIJING, April 30 -- Non-performing loans (NPL) of major Chinese commercial banks edged up in the first quarter, fresh evidence of growing pressure for industry titans to improve the quality of their loans after years of lending sprees.

The NPL of China's four largest state-owned commercial banks all rose in the first quarter according to their first-quarter profit reports, the Shanghai Securities News reported on Wednesday. According to the report, the Agricultural Bank of China (ABC) has the highest NPL ratio.

The NPL ratio of the Industrial and Commercial Bank of China, the country's largest bank, rose by 0.03 percentage point to 0.97 percent by the end of March, with its NPL increasing 6.86 billion yuan (1.11 billion U.S. dollars) from three months ago. ABC saw its NPL grow by 4.2 billion yuan during that period, with its NPL ratio hovering at 1.22 percent.

The NPL ratio of the Bank of China inched up 0.02 percentage point from three months ago to 0.98 percent by the end of March, and that of China Construction Bank edged up 0.03 percentage point to 1.02 percent during the period.

Non-performing loans refer to loans that are in default or close to being in default, while the NPL ratio is the ratio of NPL to a lender's total loans.