China's foreign exchange reserves rose 30.3 percent year-on-year to hit 3.1975 trillion U.S. dollars by the end of June, the People's Bank of China (PBOC) said Tuesday.

The foreign exchange reserves increased $138 billion in the first three months this year, excluding effects of changes in the exchange rate and asset prices, according to revised figures posted on the State Administration of Foreign Exchange's (SAFE) website Monday.

Investment returns of China's forex reserves have maintained steady for years, the SAFE said on its website in May.

In recent years, the PBOC has been using newly issued yuan to purchase most of the foreign exchange that has entered China, which has led to an increase in money supply and has intensified inflationary pressures.

It will continue its "high-pressure" clampdown on inflows of hot money, or speculative capital, to ensure financial and economic stability, said SAFE.