A toddler has died in a horrific accident in a provincial Russian city.

According to Russian reports, 26-year-old Tatyana Didenko was pushing her son Kirill in his stroller near her apartment building in Bryansk, southwest of Moscow.

A huge crater opened up under her feet after a footpath buckled, forcing her and the baby to fall in.

The woman was rescued by her policeman husband who happened to be nearby.

The fate of the boy was unknown for a day after his stroller was overturned at the bottom of the pit and he entered the city’s sewerage system.

His body was eventually found 28 hours later, nearly six kilometres away from where he disappeared.

It’s believed a sewerage main had ruptured underground some point before which had eroded the soil underneath the concrete pavers of the pathway.

The horrific accident highlights the continuing problems from Russia’s Soviet-era infrastructure which is breaking apart after years of underinvestment.

“The washout occurred because the collecting pipe rusted,” Vasily Nozdrya, a public-works official in Bryansk, told the newspaper Komsomolskaya Pravda. “We didn’t change it in time.”

He said that 70% of the pipes were past their replacement dates, but hadn’t been fixed because the city had no money for repairs.

"We have to start rebuilding things because otherwise, God forbid, this might happen again," regional head Nikolai Denin said.