mjhjmtu

I can find no clear information regarding the use of the launch escape system in today's Soyoz MS-10 abort-to-ground. The failure seems to occur just as LES jettison is scheduled to take place.

The live webcast commentator is clearly describing the events as planned, not as they unfolded, so it is not clear how the Soyuz cleared the rocket without an LES.

No, the Launch Escape System was not used.

The announcer was basing their reporting based on canned telemetry, and did not realize what was going on until after the canned telemetry showed the first stage separation.

These details are still developing, but it appears that during the separation of the strap-on boosters, one of the boosters hit the core stage.

It is a tradition for Soyuz rockets to include a plush toy suspended above the crew on an elastic cord as a quick-and-dirty G-force indicator. About 2 minutes 40 seconds into the video that NASA released of the launch (link to YouTube), during the booster separation, we see an internal shot of the capsule where the toy is suspended to about 3 Gs, then instead of going to just 1.5 Gs as expected, it becomes weightless and the internal cameras glitch out, likely due to the directional antenna not being aligned properly any more.

Next we see the strap-on boosters flying away asymmetrically, instead of the usual Korolev Cross, we see 3 boosters tumble away, signs of heavy debris, and the exhaust from the core stage is very asymmetrical.

The video then goes on to show the canned telemetry, but we can hear the translator quietly in the background giving details about loss of thrust as they translate the crew's broadcasts.

The LES tower was not jettisoned, but also was not used. This is likely because there was no debris to escape from due to still being well within the atmosphere, and no explosion to forcefully shove debris towards the crew. Without immediate danger to the crew, there was no need to subject them to the 14 Gs of acceleration that the Soyuz LES tower produces.

The crew would have performed an emergency separation from the rocket, which consists of detaching the Service Module from the third stage and jettisoning both the LES tower and fairing at the same time, firing the Service Module's engines momentarily to get away from the rocket, then detaching the Entry Module from the Orbital Module and Service Module. Aerodynamic drag would further separate the Entry Module from the rest of the spacecraft.

Scott Manley produced a video further highlighting details of the abort, where I get some additional information from.