A 30-year-old woman and her toddler son were killed after an under-construction pillar of the "Namma Metro" (Bangalore Metro) here collapsed on Tuesday, police said.

According to police, the incident took place around 11 am on Outer Ring Road near HBR Layout in the city, when the TMT bars erected for the construction of a pillar fell on their scooter. The height of the pillar is said to be over 40 feet and weighing several tonnes.

The duo was immediately rushed to a nearby hospital by the bystanders, but the woman and her two and a half year-old son succumbed to their injuries.

"Both suffered head injuries, we tried our best to save them. There was lot of blood loss already and also fall in blood pressure," doctors who treated them said.

The woman's husband and other child, who were injured, are doing fine, they added.

Addressing reporters in Dharwad, Chief Minister Basavaraj Bommai assured an inquiry into the incident and compensation to the bereaved.

"I just got to know about it, we will get it investigated... we will ascertain the reason for the collapse of the pillar and provide compensation," he said.

A case has been registered and investigation will follow, the police said.

The incident had resulted in traffic jam for some time along the stretch, even as many vehicles were plying when the mishap occurred.

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