China's?first cross-province Metro project, linking Shanghai and neighboring Jiangsu Province, has been approved by the National Development and Reform Commission, sources said yesterday.

Work is expected to begin on the line, an extension of the city's Metro Line 11, by the end of the year, according to Xinhua news agency.

The line is due to be open by 2012 and will cost 1.7 billion yuan (US$255 million).

The line will start from Shanghai's Anting Station of Line 11 and end at Jiangsu Province's Kunshan City, northwest of Shanghai.

The new section, about 6 kilometers long, will include three elevated stations.

It may be further connected at Kunshan to the Metro system of neighboring Jiangsu cities, such as Suzhou. This will help improve public transport in the Yangtze River Delta region.

For now, Line 11 connects suburban Jiading District to downtown Shanghai. The line will also expand to the city's southern Pudong area.

Meanwhile, another city subway, Metro Line 13, is also being extended. Construction work has already started, said the builder, Shanghai Shentong Metro Group.

Line 13's extension in the northwest of the city, from Jiading to downtown, should be complete by 2014.

Line 13, the only subway operating inside the World Expo site with its three stops, currently handles about 100,000 Expo visitors a day.

Shentong said yesterday that it was as yet unclear whether all the existing Line 13 stations will remain in service after the Expo.

Metro operators have also introduced yellow-marked "No Line-up" zones on platforms of Caoyang Road Station.

This practice is intended to improve rush-hour safety by prohibiting queuing during peak times, officials said.