DUBLIN • Sinead O'Connor sparked off alarm when she said in a video: "I'm fighting, fighting, fighting... to stay alive."

But an unidentified person on the Irish singer's Facebook account later wrote that she "is safe, and she is not suicidal".

In the post, made in a New Jersey motel last Thursday, O'Connor, 50, who has been diagnosed with bipolar disorder, said: "For the last two years, my entire life has been revolving (around) just about not dying.

"I'm all by myself and there's absolutely nobody in my life except my doctor, my psychiatrist" - the only helpline keeping "me alive".

She disclosed that she is suffering from three mental illnesses and has felt isolated since losing custody of her 13-year-old son.

That distress prompted singer Annie Lennox to respond on Tuesday on Facebook that she is "concerned for the safety" of the singer, reported Agence France-Presse.

"Are there no close friends or family who could be with her to give her some loving support?

"It's terrible to see her in such a vulnerable state," noted the former Eurythmics singer.

According to The Independent, police went to the motel to conduct a welfare check, but O'Connor was not in her room.

She is best remembered for her arresting 1990 rendition of Prince's song Nothing Compares 2 U, with its iconic video featuring her tearful and shaven-headed.

She quickly developed a name for inflammatory outbursts and caused an international controversy in 1992 when she tore up a picture of Pope John Paul II on an American television show.

In recent years, her posts on social media often threatened legal action against former associates and gave updates on her physical and mental health woes as well as rifts with her family and children.