Image copyright Reuters Image caption Ortega was given the maximum sentence of life without parole

A nanny convicted of murdering two children she stabbed at their luxury New York City apartment has been sentenced to life in prison.

In sentencing Yoselyn Ortega, 56, the judge described her as "pure evil" before handing her the maximum term.

The bloody bodies of Lucia "Lulu" Krim, six, and her brother Leo, two, were found by their mother in a bathtub at the Manhattan flat on 25 October 2012.

Ortega had pleaded insanity but the jury rejected her defence.

On Monday, Ortega appeared visibly shaken as she apologised while addressing the court.

Speaking in Spanish through a translator, she said she was "sorry for everything", adding that she hoped for "a great deal of forgiveness".

'Like a horror movie'

During the two-month trial at the Supreme Court in Manhattan, the mother of the victims Marina Krim told the court how she had come home with her third child, three-year-old Nessie, after Ortega did not turn up at Lulu's dance class.

She described how she had then witnessed Ortega stabbing herself in the neck in an apparent suicide attempt.

Ms Krim was later found by police crying and screaming hysterically, clutching on to her surviving child.

"I just wanted to wake up from this nightmare that I knew wasn't a nightmare. It was real," Ms Krim had told jurors. "It's like a total horror movie."

After two days of deliberations, the jury found Ortega guilty of four charges: two counts of first-degree murder and two counts of second-degree murder.

Prosecutors said the nanny was disgruntled because she felt she was being overworked by the family at the Upper West Side apartment.

Ortega was also struggling to pay tuition fees for her 17-year-old son, whom she had brought to the US from the Dominican Republic and enrolled in a private school.

The nanny's defence team argued she suffered from "chronic mental illness" and was mentally incapable of being held responsible for her actions. Her lawyer said she had hallucinated an order from the devil "to kill the children and herself".

Kevin Krim, the children's father, was away on a business trip at the time of the 2012 killings. Both parents left the courtroom before the sentence was passed.