Britain on Thursday refused to confirm reports that a US drone had killed a middle-aged British mother, also known as the "white widow", who had joined Islamic State jihadists in Syria.

Tabloid newspaper The Sun said US authorities had told them that Sally Jones, a former singer in a rock band, and her 12-year-old son died in June near the border with Iraq.

The Times also quoted a Whitehall source saying: "The premise that Sally Jones and her son are dead is probably accurate."

Defence minister Michael Fallon would not confirm the report when asked by journalists, saying: "I am not going to comment on the specific strike report.

"I can confirm that if you are British national in Iraq or Syria and you have chosen to fight for Daesh (IS)... then you have made yourself a legitimate target and you run the risk... of being of the wrong end of an RAF or US missile strike," he added.

Army colonel Ryan Dillon, a spokesman for the US-led coalition against IS, earlier tweeted that he "cannot confirm death of ISIS propagandist Sally Jones as a result of a coalition strike," in a message that was retweeted by the British government.

Jones became Britain's most wanted woman after leaving her home in Kent, south east England, in 2013, to join IS, taking son Jojo with her.

The boy's grandparents identified their grandson in an IS propaganda video released last year, in which he brandished a pistol behind a row of prisoners, immediately before they were murdered.

Jones, 50, also went by the name Sakinah Hussain, or Umm Hussain al-Britani, and once said she wanted to behead Christians with a "blunt knife".

She became radicalised after travelling to Syria following an online romance with convicted computer hacker and IS member Junaid Hussain, who died in a 2015 drone strike.

source: AFP