In initial deals, London's benchmark FTSE 100 index inched 0.1 percent higher to stand at 7,112.61 points.

In the eurozone, Frankfurt's DAX 30 gained 0.2 percent to 11,518.17 points and the Paris CAC 40 also added 0.2 percent to 5,110.80 compared with Monday's closing levels.

Tuesday's US vote is widely seen as a referendum on President Donald Trump's performance since taking the White House.

Most experts expect the Democrats would win the House of Representatives, while the Republican party would hold onto control of the Senate, dealers said.