The condition of two toddlers clinging to life after an apartment fire in Surrey, B.C. has been downgraded to critical.

Twenty-month-old Ava and Samantha have been in hospital since they were rescued from a fire in their home on Tuesday evening. Fire crews believe the blaze was sparked when the light bulb of a lamp came into contact with some bedding.

After being briefly upgraded to serious condition, the twins' condition is now listed as critical.

Their family is devastated.

"We are at our darkest hour. Ava is fighting for her life as we speak and if she doesn't improve in the next few hours we have been told we'll have to say our goodbyes," grandmother Dawn told CTV News.

"Samantha has survived another surgery this morning, and as far as I know she is critical, but stable."

The girls have an older brother, who's three. The children were all at home with their mother when the blaze broke out.

A trust fund has been set up for the twins at Coast Capital Savings. Anyone interested in donating can visit any branch and say they are interested in supporting "Ava and Samantha in Trust."

With a report from CTV British Columbia's Maria Weisgarber