Two people have been taken to hospital following an assault in southeast Calgary.

Witnesses say they saw a man lying on the front steps of an apartment covered in blood, with stab wounds in his chest. Police say a second person – a woman –  was stabbed in the head. The man is in critical condition, while the woman's wounds aren't life threatening.

It happened around 8 a.m. in an apartment building on 86th Avenue near Macleod Trail and Heritage Drive on Monday. One suite in the building is sealed off. Officers are waiting for a search warrant before the can go inside and look for a possible weapon.

Carol Burley was having her morning coffee and doing some homework when she heard a bunch of noise at the neighbouring apartment building.

"I just heard a bunch of yelling of screaming, I heard a girl say 'no, stop it, stop it.'  And then I heard a big smash of glass."

Burley went outside to see one of the victims covered in blood.

"His face, his chest, his legs, it was everywhere, it was running down the staircase that he was lying on. Then he got up off the staircase … walked over to the bush and collapsed."

A second man is in custody and police are speaking to him.

"We're just trying to ascertain their role in the incident," said acting duty Staff Sgt. Paul Wozney.

People living in the neighbourhood say police are often at the apartment buildings in the area.