Image copyright Getty Images Image caption The organisation works around the world combating a range of humanitarian issues

The US Justice Department has opened a new inquiry into the Clinton family's non-profit organisation, the Clinton Foundation, US media report.

The Attorney General and FBI will reportedly investigate claims Hillary Clinton engaged in so-called "pay-to-play" politics for donations.

Mrs Clinton's spokesman on Friday labelled the inquiry a "sham".

He said Attorney General Jeff Sessions was doing President Trump's bidding to distract from the Russia probe.

What will inquiry focus on?

The FBI has been quietly investigating the Clinton Foundation for months, according to people familiar with the inquiry, US media report.

The investigation is reportedly being led by FBI agents from Little Rock, Arkansas, where the foundation was founded.

They have interviewed at least one witness in the last month, reports the Hill, a Washington DC political news outlet.

Agents are said to be looking into whether policy favours were traded for unspecified donations to the foundation while Mrs Clinton was secretary of state.

But figures within the Justice Department and FBI doubt any charges will be brought, the Washington Post reports.

Image copyright Getty Images Image caption Republicans have been urging Attorney General Jeff Sessions to appoint a special counsel to look into the Clintons

The FBI began looking into the foundation in 2015, but the inquiry was put on hold amid election season a year later.

Why is the foundation controversial?

US media outlets including the New York Times in recent years have scrutinised the Clinton Foundation.

Reports have explored possible links between contributions and speech fees received by the charity and decisions by Clinton's State Department that benefited donors.

Many of the allegations were detailed in conservative author Peter Schweizer's 2015 book Clinton Cash.

Founded in 1997 by former US President Bill Clinton, the Clinton Foundation has become a multi-billion dollar organisation.

It has projects around the world focusing on women's heath, climate change and economic development, according to its website.

Mr Clinton remains the foundation's president, and the couple's daughter, Chelsea, sits as vice-chair.

Mrs Clinton pledged to have no formal role in the charity while serving as secretary of state from 2009-13.

Image copyright Getty Images Image caption The foundation has been involved with initiatives around the world since 2001

In November last year the US Justice Department asked prosecutors to look into the charitable foundation and a deal to sell a uranium company.

But Mr Sessions at the time told a Senate hearing there was no basis to appoint a special counsel to investigate the "Uranium One" sale.

What's the reaction?

Clinton spokesman Nick Merrill railed against the new Justice Department inquiry.

"The goal is to distract from the indictments, guilty pleas, and accusations of treason from Trump's own people at the expense of our justice system's integrity," he said.

"It's disgraceful, and should be concerning to all Americans."

A spokesperson for the Clinton Foundation itself said the investigation would not distract its humanitarian work.

"Time after time, the Clinton Foundation has been subjected to politically motivated allegations, and time after time these allegations have been proven false," said spokesman Craig Minassian.

However, the inquiry will be welcomed by President Trump, who has frequently called for investigations against the former secretary of state, whom he calls "crooked Hillary".

What other Clinton-linked inquiries are afoot?

On Friday, two top Republicans referred the former British spy who wrote a dossier of allegations about Donald Trump for possible criminal charges.

Senate Judiciary Committee chairman Chuck Grassley and fellow panel member Senator Lindsey Graham suggested the Justice Department investigate whether Christopher Steele had lied to the FBI.

Mr Steele's political-opposition research report - reportedly bankrolled partly by the Clinton campaign - suggested the Trump campaign was complicit in Russian political meddling in the US.

Separately, there are reports that the Justice Department is looking back into Mrs Clinton's use of a private email server while she was America's top diplomat.