Chinese online travel booking firm Qunar has received a fresh $500m (£328m, €457m) in funding from investors led by US private equity firm Silver Lake.

Silver Lake invested $330m in Qunar's convertible bonds, and another undisclosed investor provided the remaining $170m.

Qunar said it will use the capital to continue to expand its mobile presence, grow business lines and further enhance technology capabilities.

"Silver Lake's technology-enabled travel industry expertise and strong track record in value creation make it the ideal partner for Qunar as we move into our next phase of growth," said Chenchao Zhuang, CEO of Qunar.

"The capital will help the company fuel its rapid expansion and pursue a leadership position in China's travel industry across all segments."

"Qunar is a nimble, fast-growing leader in mobile and online travel bookings, with a technology-driven operating model that gives it a competitive advantage," said Silver Lake Managing Director Zheng Wang.

"Chinese consumers are spending more money on travel and are increasingly using mobile devices to book their travel related activities. We believe the company is well-positioned to address these secular trends, and under the leadership of Qunar's strong senior management team, continue to deliver outstanding growth for the company."

The company separately said in its first quarter earnings release that it had rejected an unsolicited acquisition offer from rival Ctrip.com International, received on 8 May. However, it noted that it "remains open to engaging in further discussions with Ctrip as well as with other strategic players in our sector".

In addition, Qunar entered into a business cooperation agreement with its majority stakeholder Baidu, under which the internet giant has agreed to grant Qunar an exclusive right to integrate hotel information and products into the PC and mobile app versions of Baidu Maps.

Under this agreement, Qunar will display location-based hotel data through the Baidu Maps interface. Users can click on the displayed hotels to view hotels and to complete bookings.