Image copyright Courtesy Piper Killen Image caption The woman was stranded for about five hours

Toronto police have arrested a woman for mischief after she climbed a construction crane and became stranded.

Authorities say they received a call alerting them to a person climbing the crane in downtown Toronto shortly after 03:00 local time (08:00 GMT).

It took hours for the city's police and fire services to rescue the woman in a high-wire operation authorities called "technical and complex".

Why she climbed the nearly 12-storey high structure remains a mystery.

After what Toronto Fire Services District Chief Stephan Powell called "heavy deliberations" by various emergency service teams over how to rescue the woman, a high-angle specialist climber was brought in to rappel up the crane around 6am.

Toronto firefighter Rob Wonfor had to slowly climb up the inside the crane and reach the woman, who had lowered herself on a block hanging from the structure.

The precarious rescue was "not a speed sport", Powell said. "Every step has to be thought out."

Image copyright Courtesy Piper Killen Image caption Rescuers bringing down the woman on the crane

An Emergency Task Force officer, specialised in high-risk situations, was also sent up the crane to speak to the woman and keep her calm.

Once Mr Wonfor reached her, he placed her in a harness and secured her to a safety line. Both were then lowered to the ground by about 8:30am.

Spectators who had gathered to watch the morning rescue applauded.

Toronto Fire Chief Matthew Pegg called it a highly technical operation.

"There isn't a text book on that but I think we just wrote it," he said.

Image copyright Courtesy James Gunn Image caption Fire services took over two hours to rescue the woman

Mr Wonfor told journalists after the more than two-hour long rescue that his first thought was: "How did she get up there"?

He said the woman, who climbed the structure with no equipment, was calm during the whole event.

"She has to tell me how she did it because she's going to be our new training officer for high-angle rescues, because it's impressive," he said.

The woman was brought to hospital following the rescue and will be questioned by police later on Wednesday.