Hillary Clinton apologies for using private email server while serving as US Secretary of State

The presidential candidate had previously declined to apologise over the controversy

Hillary Clinton, who is the front-runner for her party's 2016 presidential nomination, has been criticised for using the unsecured server while she was secretary of state (Reuters)

Hillary Clinton, the presidential candidate and former secretary of state, has apologised for using a private email server at her home while serving as the US’s top diplomat,

After months of controversy over the use of the server at her home in New York, the Democratic frontrunner sought to draw a line under the issue.

“That was a mistake. I'm sorry about that. I take responsibility,” Ms Clinton, said in an interview with ABC News, to be broadcast on Tuesday evening.

Hillary Clinton is embroiled in a row over her e-mails when she was Secretary of State (Getty)

In two earlier interviews in the past week, Ms Clinton had declined to apologise for the controversial email arrangement while working at the State Department, saying it was allowed.

Reuters said Ms Clinton has been forced to defend herself against growing scrutiny by journalists and political opponents of how she handled sensitive government information since the email arrangement first came to light in March.

The Federal Bureau of Investigation is now examining the server to see whether any information, including classified information, was mishandled.

Initially, Ms Clinton said she handled no classified information on her unsecured private email server, a practice which the government forbids. More recently, she has said she sent and received no information that was “marked” that way.