More subway lines planned for hometown of Terracotta Army

Xi'an, one of the oldest cities in China as well as the home of world-famous Terracotta Army, plans to add nine more subway lines to its metro system, the city's subway office said Wednesday.

As the capital of northwest Shaanxi province, Xi'an has been working to build itself into a metropolis in the country's relatively undeveloped western region.

The city opened its first subway line in September last year, making it the first subway line in the country's northwest.

The latest announcement raised the city's number of planned subway lines to 15. The total length of the 15 lines is estimated at 550 kilometers, according to a statement released by the subway office on Wednesday.

However, the statement did not mention the timetable for the construction of the newly-announced lines.

Previously, six subway lines with a total length of over 200 km were scheduled to be built in Xi'an by 2018 as part of the city's ambitious plan to become one of China's largest urban areas.

Plans have been made to integrate Xi'an with the neighboring city of Xianyang to create a single metropolitan area with more than 13 million residents.