A makeshift memorial is left outside the Krim family apartment in New York, October 28, 2012. Photo: REUTERS/Carlo Allegri

NEW YORK - A New York nanny accused of the stabbing deaths of two young children last month pleaded not guilty to murder charges Wednesday in a rare judicial proceeding conducted inside a hospital where the 50-year-old woman is recovering from self-inflicted wounds.

Yoselyn Ortega was indicted two weeks ago on two counts each of first- and second-degree murder in the killings of Lucia Krim, 6, and her brother, Leo, who was days shy of his second birthday, in their parents' luxury apartment.

Ortega entered the not-guilty plea from her hospital room at New York-Presbyterian/Weill Cornell Medical Center, according to a pool report of the proceeding. She has been in the hospital since Oct. 25 recovering from what police have described as stab wounds she inflicted on herself at the scene of the murders.

The children's mother, Marina Krim, discovered their bodies in the bathtub when she returned to their Upper West Side home from a swimming lesson with a third child, police have said. Ortega then began to stab herself in front of Krim.

Ortega was formally arrested earlier this month after police interviewed her for the first time in her hospital room.

Ortega had been employed by the Krim family for two years, police said. She lived with her son and sister near the Krims' apartment off Central Park and has been a naturalized U.S. citizen for a decade.

Marina Krim had expected to meet Ortega and the two children at a local dance studio on the day of the killings. Upon finding the lights out in the apartment, Marina Krim asked the doorman if Ortega had taken the kids out, police said.

Krim then re-entered the home and found the children in the bathroom before encountering Ortega.

Kevin Krim, the children's father and a CNBC executive, had been heading home from a business trip at the time of the killings, police said. - Reuters