BBC news said this morning one A/C had sent out a "hijack alert" and the newsman described it as an "airbourne SOS". I presume that one of the pilots had managed to squwark 7500. Thats all that i can add really, except to say that if it is the Chechens, i hope this doesn't affect other nations aviation industries, as this is a particularly unfortunate russian problem.
Sad day.