The accident happened Saturday morning in poor weather conditions when a broken-down Toyota minivan was struck from behind on Highway 1 near Coquitlam, 10 miles east of Vancouver, The Province newspaper reported.

Two boys, ages 6 and 9, died of their injuries Sunday afternoon, while their 8-year-old brother and two elderly women also in the van were listed in critical condition Monday, the Canadian Broadcasting Corp. reported.

The van was carrying eight people when it stopped. The others in the van received minor injuries after a BMW SUV struck it from behind, and the SUV was then struck by another vehicle behind it.

Two other drivers received minor injuries and will be charged for being alone in their vehicles in the HOV lane, RCMP Cpl. Peter Thiessen said, adding there were unanswered questions about the minivan driver's actions.

"There was enough room to pull over to the left side of the roadway to get out of the travel portion of the HOV lane," Thiessen said. "It isn't clear why she did not, or was not able to do that, whether a mechanical issue or a fire prevented her from doing that."