China on Wednesday urged the United States to protect investor interests as US lawmakers remained at odds over how to slash the country\'s deficit and avoid a devastating default. US politicians must agree to raise the $14.3-trillion debt ceiling by August 2 or else Washington will likely miss out on its repayment obligations, sending it into default, which would have seismic ripples around the global economy. \"We hope the US government will take responsible measures to boost confidence of the international financial markets, respect and protect investor interests,\" the State Administration of Foreign Exchange said in a statement. The comments echoed those of foreign ministry spokesman Hong Lei, who last week called on Washington to adopt a \"responsible policy and measures to ensure the interests of investors\". SAFE said it had noted the opinions of credit ratings agencies including Standard & Poor\'s, which last week placed the United States on downgrade watch following a similar move by its counterpart Moody\'s. A downgrade could sharply raise US borrowing costs, worsening the country\'s already dire fiscal position, and send shock waves through the financial world, which has long considered US debt a benchmark among safe-haven investments. China is by far the top holder of US debt, with holdings at $1.16 trillion in May, according to the latest US data, and has raised concerns about its investment in the past. Beijing has warned that the massive US stimulus effort launched to revive the economy after the global downturn would lead to mushrooming debt that erodes the value of the dollar and its Treasury holdings.