President Trump's approval rating dipped by 4 percentage points to start March, according to a new poll, dropping below 40 percent.

The Gallup poll released Thursday showed Trump with a 39 percent approval rating, down from 43 percent in the second half of February. Trump closed the month with an unsuccessful summit with North Korean leader Kim Jong Un and saw his former personal attorney Michael Cohen deliver explosive testimony before House lawmakers. March also opened with a less-than-stellar jobs report.

Trump's approval rating is buoyed in large part by Republicans, 90 percent of whom gave him positive marks in the Gallup poll. Thirty-three percent of independents approve of Trump, as do just 4 percent of Democrats, according to the poll.

The poll surveyed 1,039 people from March 1 to 10 and has a margin of error of 4 percentage points.

Trump's approval rating has consistently hovered around 40 percent for much of his presidency. A RealClearPolitics average of approval rating polls shows him with a 43 percent approval rating.

The new Gallup poll was released amid a week in which Trump is set to face two rebukes from the Senate.

Senators on Wednesday passed a joint resolution calling for an end to U.S. support of the Saudi-led military campaign in Yemen. On Thursday, the Senate is expected to pass a resolution to block the president's national emergency declaration at the southern border.

Trump has indicated he will veto both measures.

In addition, Trump's former campaign chairman, Paul Manafort, was sentenced last week to just under four years in prison for his conviction on various financial crimes. His total sentence was increased to 7 1/2 years on Wednesday after an appearance in Washington, D.C., court on separate charges. Manafort on Wednesday was also charged with fraud by Manhattan prosecutors.