The exhaust of the escaping capsule started a fire, leading to explosions that destroyed the rocket, severely damaged the launch pad, and directly killing one person.
After a few minutes, the core stage and strap-ons exploded, completely destroying the entire launch vehicle and causing major damage to LC-31.
[2] Since tracking cameras around LC-31 had been turned off when the launch aborted, there was no film footage of the fire or explosion for analysis, but telemetry data found that the igniter in the Blok D strap-on had failed to activate.
Initially, it was suspected that the booster had been bumped when the gantry tower was put back in place following the abort and that this somehow managed to trigger the LES, but a more thorough investigation found a different cause.
On the other hand, the LES had also worked flawlessly and demonstrated its ability to safely pull cosmonauts from the booster should an emergency arise as it did years later in the Soyuz 7K-ST No.16L abort (26 September 1983).