NEW YORK (Reuters) - The number of Americans who believe President Donald Trump should be impeached rose by 8 percentage points over the past week as more people learned about allegations that Trump pressured Ukraine to smear his top Democratic political rival Joe Biden, according to a Reuters/Ipsos poll released on Monday.

The Sept. 26-30 opinion poll found that 45% of adults believe Republican Trump “should be impeached,” compared with 37% in a similar poll that ran last week. Another 41% said that Trump should not be impeached and 15% said they “don’t know.”

Among Democrats, 74% said Trump should be impeached, up 8 points over the past week, while 13% of Republicans said they supported impeachment, up 3 points. It was unchanged among independents at 37%.

The poll findings mirror several other recent opinion polls, which have shown that public support has increased recently for an impeachment inquiry into Trump.

Full poll results: tmsnrt.rs/2n3AYWx

The American public has been increasingly focused on the question of impeachment following a whistleblower complaint about a July phone call between Trump and Ukrainian President Volodymyr Zelenskiy.

The U.S. House of Representatives initiated an impeachment inquiry of Trump last week after a whistleblower report raised concerns that Trump tried to leverage nearly $400 million in U.S. aid in exchange for a political favor from Zelenskiy involving an investigation of Joe Biden, the former vice president and leading Democratic presidential contender.

The poll of more than 2,200 U.S. adults found that 34% had heard “a great deal” about the Ukraine scandal this week, about twice the number of people who had been paying close attention when compared with last week. Another 30% said they have heard “some” details about the Ukraine call.

When asked what they thought about the news, 43% said “president Trump is trying to smear Joe Biden ahead of the 2020 presidential campaign,” up 4 points from last week.

The poll also found that 66% of American adults said any elected official “should be removed” from office if they work with a foreign government to attack a political rival. That included 46% of Republicans, 88% of Democrats and about two-thirds of independents.

The fact that a smaller number of respondents - 45% - said that Trump should be impeached, however, suggests that many of them did not believe allegations against Trump or had yet to conclude Trump had indeed worked with Ukraine to damage Biden.

Public opinion may continue to shift as more information is revealed. But University of Michigan political scientist Nicholas Valentino said that support for Trump’s impeachment should level off unless Republican leaders join Democrats in publicly criticizing the president.

“People aren’t constitutional scholars,” Valentino said. “They trust their elected officials from their party to know the rules of politics. And when members of their own party say that someone has broken the rules, that’s when public opinion will really begin to change.”

The Reuters/Ipsos poll was conducted online, in English, throughout the United States. It gathered responses from 2,234 adults, including 944 Democrats and 855 Republicans. It has a credibility interval, a measure of precision, of 4 percentage points.