China's foreign exchange investment is based on the principle of profitability, liquidity, security, said Assistant Minister of Finance Zhu Guangyao on Friday.

Zhu made the remarks in a press briefing after the fifth China-US Strategic Economic Dialogue(SED) concluded on early Friday. He was asked to comment on the country's further possible increase in its holdings of US Treasury bonds.

"We hope China and the United States, under a stable global economic situation, could increase investment in each other so as to promote economic, trade and investment ties between our two nations," Zhu told reporters.

"This will help China and the United States to achieve mutual benefits and build constructive cooperative partnership," he added.

China is now the top holder of US government bonds, owning $585 billion of Treasuries as of late September and overtaking Japan as Washington's top foreign creditor.

According to Zhu, the US direct investment in China has exceeded $59 billion.

"We hope the US side will take our concerns seriously and make concrete efforts to protect Chinese investors' interests," Zhu said.