Baidu Inc., which operates China's most popular search engine, says its quarterly profit rose 34 percent over a year earlier as its mobile business grew.

Baidu said Friday it earned 3.5 billion yuan ($571.1 million) in the three months ended June 30. Revenue rose 58.5 percent to 11.9 billion yuan ($1.9 billion).

Baidu and other Internet companies are building mobile e-commerce and other services as Chinese users shift rapidly to going online using smartphones and tablet computers. Baidu dominates traditional Internet search but is a much smaller presence in mobile.

The contribution of mobile to Baidu's total revenue rose above 30 percent for the first time, chairman Robin Li said in a statement.

Li said, "We had a great quarter as we continued to build very strong mobile momentum."