Cut-throat competition leads to Unicom gloom

China's second-largest mobile carrier China Unicom posted a 68 percent plunge in first-quarter net profit, lagging expectations, partly due to costs from adding third-generation service as intense competition continued to pressure its margins.

Expenses for the early stages of Unicom's 3G business, depreciation, marketing and other expenses was "relatively significant," the company said in a statement.

Unicom's weak results come on the heels of those from rival China Mobile, the world's largest mobile carrier by subscribers, which last week reported flat year-on-year first-quarter profit growth due to stiff competition and heavy spending on new third-generation mobile networks.