Net profit of China's leading online travel site Ctrip.com fell 25 percent despite 36-percent growth in business revenues, as a "price war" in the sector raised marketing costs and diminished profitability.

Ctrip, the Nasdaq-listed travel operator, said in its financial statement released on Thursday that its net profit retreated 25 percent from a year ago to 115 million yuan (18.68 million U.S. dollars) in the first quarter, even though its net business revenues jumped 36 percent year on year to 1.6 billion yuan during the period.

Compared with the fourth quarter of last year, profit declined by 56 percent, as Ctrip announced at the end of 2013 it would spend 500 million yuan in marketing and promotion.

The deep decline was due to hiking sales and marketing fees, which jumped 61 percent year on year to 430 million yuan, Ctrip said.

Helped by its mobile phone app, Ctrip posted strong growth in hotel bookings, sales of travel tickets, tourism vocation and business trip management, with transaction volume of hotel booking and ticket sales soaring by 67 percent and 71 percent respectively.

With a growing number of Chinese turning to smartphones to book accommodation or travel tickets, about 40 percent of hotel booking transactions were submitted by mobile phones, according to Ctrip.

Whether Ctrip's profit will remain under pressure is still unknown as media reports in March said a loophole in its site could lead to leaks of users' payment information. Ctrip immediately fixed the problem.

The firm expected its net revenue to grow 30-35 percent in the second quarter.