Mainland and Hong Kong stocks opened lower on Thursday, dragged down by tech shares, as investors worried about the potential impact on the sector from the upcoming US presidential election.

China's blue-chip CSI300 Index eased 0.4 percent, while the Hong Kong benchmark Hang Seng opened 0.89 percent down at 20,576.

The Hang Seng Tech index lost about 1.35 percent. (Reuters)