BEIJING - Chinese banks saw their net foreign exchange sales jump by nearly 150 percent from June to $31.7 billion in July, official data showed Tuesday.

Chinese lenders bought $111.3 billion worth of foreign currency last month and sold $143 billion, the State Administration of Foreign Exchange (SAFE) said in a statement.

The amount of net sales in July was higher than $12.8 billion in June, $12.5 billion in May and $23.7 billion in April, but lower than $36.4 billion in March.

A SAFE spokesperson attributed the increase to the short-term impact of Brexit and seasonal factors, calling it a fluctuation "within the normal range."

Brexit, Britain's vote to leave the European Union, in late June led to depreciation of the yuan against the dollar and resulted in more market demand for forex in the beginning of July, a separate SAFE statement quoted the spokesperson as saying.

That impact has moderated and is controllable, according to the statement.

It also noted that forex demand in July is typically higher than other months as many foreign companies in China remit profits overseas in July, which is also the high season for overseas travels.

Despite the monthly rise, the forex market remains calm, the spokesperson said, predicting stable and more balanced capital flow in the longer-term.