An American woman has admitted killing her three children in Edinburgh last year.

Theresa Riggi stabbed her eight-year-old twins Austin and Luke and their five-year-old sister Cecilia at their home in the city.

Their bodies were discovered following a suspected gas explosion in August last year at the townhouse they shared with Riggi, originally from the States, in the Scottish capital's Slateford Road.

At the city's High Court today, Riggi, 47, entered a plea of guilty to the culpable homicide of her three children on the grounds of diminished responsibility. She had originally been charged with murder.

Riggi originally faced three charges of murder but admitted the lesser charges during a hearing this morning.

Prosecutors had alleged that Cecilia and the twins, who were also known as Augustino and Gianluca, were repeatedly struck on the body with a knife or knives between August 2 and 4 last year.

She was also accused of recklessly causing a gas explosion.

The family had moved to the city from Skene, Aberdeenshire, following the breakdown of Riggi's marriage to the children's father, Pasquale Riggi.

Following their deaths, the oil engineer said he was "paralysed with grief".

Emergency services were called to the modern townhouse following an explosion on August 4.

Riggi was found badly injured after apparently falling from a second-floor balcony and the children's bodies were discovered inside.

She was arrested in connection with the children's deaths after post-mortem examinations, and a specially-convened court was held inside Edinburgh Royal Infirmary, where she was being treated.

She was later transferred to Cornton Vale Prison for women, near Stirling.

The funeral of the three children was held at the end of August at St Mary's Cathedral in Aberdeen, the city where the youngsters lived until shortly before their deaths.

Riggi and her husband were involved in a legal action over the children at the Court of Session in Edinburgh at the time of the tragedy.