BEIJING (AP) — Microsoft Corp. co-founder Bill Gates and billionaire investor Warren Buffett said yesterday they won't be pressuring China's newly minted millionaires to give up their fortunes during a trip this month to China to promote philanthropy.

Gates and Buffett have been campaigning to persuade American billionaires to give most of their fortunes to charity. Their visit to China will include a private dinner on September 29 in Beijing with a group of wealthy Chinese. According to the Bill and Melinda Gates Foundation office in China, some invitees have rung to ask if they will be required to pledge donations.

In a letter carried by the official Xinhua News Agency, Gates and Buffett said that while 40 American families have signed what they call the "giving pledge," the drive was not necessarily suited to China.

"We know that the Giving Pledge is just one approach to philanthropy, and we do not know if it's the right path forward for China," they wrote. "Some people have wondered if we're coming to China to pressure people to give. Not at all."

Gates and Buffett said they just wanted to share experiences with China's successful businesspeople, but noted the country's newly minted wealthy were at a key moment when they could make a significant impact.

"The present generation of successful entrepreneurs has an opportunity to set an example for future generations in China," the letter said. "It is very likely they will have a substantial impact on how large scale philanthropy grows and develops in modern China."