Image copyright AP Image caption Mosul in Iraq has been in the hands of so-called Islamic State since 2014

The UK is using cyber warfare in the fight against Islamic State militants for control of the Iraqi city of Mosul, the defence secretary has said.

At a conference in London, Sir Michael Fallon confirmed the Britain was, for the first time, conducting what he called "offensive cyber" against IS.

He refused to give any further details.

Mosul has been in the hands of IS, also referred to as Daesh, since 2014 and is the militants' last major Iraqi stronghold.

When asked if the UK was launching cyber attacks in the bid to take the northern Iraqi city from IS, Sir Michael said: "I'm not going into operational specifics, but yes, you know we are conducting military operations against Daesh as part of the international coalition, and I can confirm that we are using offensive cyber for the first time in this campaign."

Iraqi forces said on Thursday they had recaptured the town of Bartella, less than 10 miles (15 km) east of Mosul and Iraqi Prime Minister Haider al-Abadi said the operation to retake Mosul was progressing faster than planned.

The Iraqi army is moving from the south, as Kurdish fighters launch a large-scale operation east and north of the city.