SHANGHAI - The first phase of Shanghai's longest river tunnel has been completed construction and will start operation Thursday, two weeks before the Shanghai Expo opens on May 1.

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The Longyao Road river tunnel, 4.04 km long, starts from the intersection between Shilong road and Longwu road in Xuhui district, goes under the Huangpu River and ends at Chengshan road in Pudong district.

The first phase of the tunnel -- the section between the intersection in Xuhui district and Jiyang road in Pudong district -- ?took 25 months for construction, said a spokesman with Shanghai Construction Group, builder of the tunnel.

The Expo site, covering 5.28 square kilometers, spans across the Huangpu River and the tunnel would be a major channel for passengers getting from one side of the river to the other, said the spokesman.

Shanghai Expo 2010, with the theme "Better City, Better Life", will run from May 1 to October 31 and is expected to attract 70 million visitors.