I hit a pipe with a mower and now it won’t turn

I was mowing the other day and there was a pipe sticking out of the ground. The pipe wasn't carrying any services, just a piece of metal sticking out of the ground (I've now removed it).

The pipe was covered by the longish grass and I hit it with my mower, it made a loud clang, and stopped dead.

Now the blades on the mower are very hard/stiff to turn by hand. Using the pull starter is completely impossible, the rope would break if I pulled it any harder. I'm thinking the drive shaft may have disconnected with the engine, but I don't really know a lot about small engines.

Some more information. It's a Husqvarna mower, one year old with a Briggs & Stratton engine. The engine is still under warranty, but the closest authorized repair place is two hours from where I live.

I'm wondering if someone has come across this situation before and would know if it's an easy fix or is the mower a write-off.

EDIT:

Thank you everyone for the answers and suggestions. Due to the amount of warnings below, I'll take it to a repair place. If some more information comes in I'll post it up here.

The reason I was thinking about fixing it myself was the support person from Briggs & Stratton gave me a suggestion to buy this Repair Manual

EDIT 2:
I didn't take it to a repair place and trying myself. So starting to take it apart (spark plug is out) and get the top cover off. The main wheel that turns with the blades can rotate 2 full turn freely and then for the next 1/4 turn it is very tight, then repeats.

EDIT 3:
Success! After spinning the wheel and blades a bit more everything seemed to loosen up and now it's working! Turns over with one easy pull of the rope.

EDIT 3.5:
Because if all the interest and concern over the pipe, see photo. It was well inside my property line and I assume it was once used to hold a flag or sign.