The United States is divided over the Republican impeachment probe of Democratic President Joe Biden, according to a Reuters/Ipsos poll completed on Thursday, with a plurality of Americans supporting the idea.

Some 41 percent of respondents said they supported the idea of Congress opening an impeachment investigation into Biden related to allegations involving his son Hunter Biden, while 35 percent were opposed and 24 percent said they were not sure.

The online poll of 4,413 Americans was conducted from September 8 through September 14, meaning that some respondents answered the question before Republicans in the House of Representatives said on Tuesday they would go ahead with the investigation.

Republicans say they have found a "culture of corruption" around the business activities of Biden's son Hunter Biden that justifies an investigation. They have not released evidence of wrongdoing by the president, and the White House says the probe is a political stunt that is not backed up by facts.

The poll results found a sharp partisan divide. Only 18 percent of Democrats supported the inquiry, while 71 percent of Republicans backed it. Likewise, 63 percent of Democrats and 14 percent of Republicans said they did not support it.

Self-described independents were more evenly divided, with 38 percent supporting the probe and 30 percent opposing it and 32 percent unsure.

The investigation could lead to an impeachment vote by the Republican-controlled House. Biden would not be removed from office unless two-thirds of the Democratic-controlled Senate votes to convict - an unlikely prospect.

Biden's son Hunter pursued a wide range of foreign business ventures and has struggled with drug and alcohol addiction. He was criminally charged on Thursday with deceiving a gun dealer into selling him a firearm, in the first-ever indictment of a sitting president's child.

The Reuters/Ipsos poll found that 46 percent of respondents believed that criminal charges were politically motivated, while 40 percent thought they were not.

Previous polls have found that many Americans believe Hunter Biden has received special treatment.

The poll has a credibility interval, a measure of precision, of plus or minus 2 percentage points.