04/26/2017 03:11 EDT | Updated 04/26/2017 04:04 EDT

High drama as firefighters try to reach woman stuck on crane in downtown Toronto

TORONTO — Some streets in Toronto's downtown core were closed early Wednesday as dozens of construction workers and commuters gazed skyward to watch police and firefighters try to rescue a woman who got stuck atop a tall construction crane during the night.

Fire officials earlier said it appears the woman was trespassing and climbed up the piece of machinery at a construction site on Wellesley St. near Yonge St.

Platoon chief Kevin Shaw told reporters at the scene that crews were called at about 4 a.m.

The woman is believed to be approximately 12 storeys up and television video taken before sunrise had showed her standing atop a gently swaying large pulley device and clinging to a steel cable.

"We have about a mid-20s female who has crawled up the crane, crawled out on the end of it and slid down that cable to the big hook that she's on right now," Shaw said.

The woman was last seen sitting atop the device, which police said measures only about 15 centimetres by 60 centimetres. Some bystanders were taking photos of the unfolding drama.

"We have a firefighter going up now ... it's a slow, tedious process, but it's a safe process for our firefighter." said Shaw.

"He's going up the interior of the crane right now. Once he gets to the top, he's going to secure himself (and) hopefully lower himself down onto the position where the female is and put her in a harness. We're waiting for a crane operator to get here (and) we may lower the crane a little bit."

Shaw said there was no immediate indication as to why the woman climbed atop the crane.

"She's been up there for a couple of hours, so she's got to be getting pretty cold and I'm sure she's scared, so it's going to take a while," he said. 

"Obviously she shouldn't be there and hopefully we can come to a good solution to this problem here."