An official in India's southern Telangana state says the chances of 8 workers being rescued days after a tunnel collapse are "very, very remote."

Telangana minister Komatireddy Venkat Reddy visited the SLBC tunnel collapse site on Monday to assess the ongoing rescue operation, as multiple agencies continue efforts to save eight workers trapped since February 22.

While rescuers have managed to cover a large part of the tunnel Tuesday — 13.79 km of the 13.85 km — the last part has been challenging because of a mix of water and slush at the collapse site.