Chinese shares closed sharply lower in the morning session Tuesday, tracking slides in regional markets amid concerns over the escalating nuclear power plant crisis in earthquake and tsunami-ravaged Japan.

The benchmark Shanghai Composite Index shed 0.33 percent to open at 2,927.98 and quickly widened its losses to 63 points, or 2.14 percent, to finish the morning session at 2,874.63 after the Tokyo stock tumbled more than 6 percent for the second consecutive trading day.

The Shenzhen Component Index slid 0.4 percent to open at 12,905.99 and fell sharply by 385.01 points, or 2.97 percent, to end the morning break at 12,573.28.