Two toddlers are clinging to life after two brothers heroically rescued them from an apartment fire in Surrey, B.C., east of Vancouver.

The blaze broke out in the bedroom where the 20-month-old twin girls, Ava and Samantha, were sleeping around 6 p.m. Tuesday.

The grandmother of the twins, Dawn, who asked that the family's last name not be used, told CTV News that the girls are in very serious condition, with burns to a large percentage of their bodies.

"They have a long road to recovery," she said. "We just ask that people continue to pray for them because it's not going to end today or tomorrow. It's going to be a long, long time."

Mounties and the family are crediting the heroism of neighbours Matthew and Simon Gallant for saving the girls.

"Ava and Samantha are strong little girls and we just really want them to be well at the end of this," Dawn said. "We are so grateful to those brave men who risked their lives to save our little girls. They're our world. We love them so much."

Matthew and Simon rushed into the apartment through thick smoke and pulled the girls off a burning bed.

"We could just see smoke and hear ‘help me, help me,'" Simon said.

"Once I opened the door to the room there was a wall of smoke. It was like a punch in the face.... You couldn't see a few feet in front of you."

The brothers were able to rescue both girls from the burning bedroom and rushed the young victims, their three-year-old brother and their mother to safety.

"I think what they did was heroic and they should be recognized for their efforts," Fire Chief Jon Caviglia told CTV News.

Matthew and Simon were treated in hospital for minor smoke inhalation.

Fire investigators say the cause of the blaze was accidental.

"It was a lamp that came into contact with some blankets and bedding and caught the contents on fire," Caviglia said.

The tots were rushed to Royal Columbian Hospital with burns over a large part of their bodies. They have been transferred to BC Children's Hospital and were listed in serious condition Wednesday afternoon.

Their mother, who was not injured, is keeping vigil at their bedside. The family had moved into the apartment in August. The father of the twins had stepped out before the fire started.

With a report from CTV British Columbia's Michele Brunoro