China's current account surplus widened sharply to 69.6 billion U.S. dollars in the second quarter of the year, the State Administration of Foreign Exchange (SAFE) said on Tuesday.

This means the surplus under the country's current account, a measure of its foreign trade, more than doubled between April and June from the first quarter's 28.8 billion U.S. dollars, according to preliminary statistics released by the SAFE.

For the capital and financial account, China posted a surplus of 67 billion U.S. dollars in the second quarter, narrowing from 86.1 billion U.S. dollars in the first three months of this year, the SAFE said.

The surpluses under the current as well as capital and financial accounts raised the country's international reserve assets by 136.5 billion U.S. dollars in the second quarter, it said.

The foreign exchange reserves increased 136.9 billion U.S. dollars during the April-June period, excluding effects of changes in the exchange rate and asset prices.