Support for Donald Trump’s impeachment has increased over the past month according to the latest opinion polls as Democrats accused Republican senators of violating their oath of office by pledging to work for the president’s acquittal.

The Democrat-controlled House of Representative is expected to vote to send Mr Trump for trial in the Senate this week accusing the president of abuse of power and obstruction of Congress.

Americans remain deeply divided over whether Mr Trump should be removed from office. However, two polls released on Sunday show that impeachment is gathering support, albeit slowly.

A Fox News poll, conducted last week, showed that impeachment and removal from office was backed by 50 per cent of voters - up one point from last month and opposed by 41 per cent, unchanged from November.

Meanwhile, a CBS poll showed 42 per cent of voters in favour of removal and 42 per cent opposed.

However, a separate survey 46 per cent of voters who took part in last month’s poll favoured impeachment, compared with 43 per cent in November.

The polls were taken against a backdrop of battle lines being drawn up for the Senate trial, which is expected to begin early next month.