a russian warplane a stab in the back by terrorist accomplices and vows serious consequences. >> translator: we will never tolerate such crimes like the one committed today. >> reporter: vladimir putin is not known to back down. and tonight analysts warn he's under pressure to respond strongly. >> there are some russians who feel like russia's response was very soft. >> vladimir putin and turkish president erdogan, they're a lot alike. they both have big egos. they both seek to portray themselves to the public as strong men who have a tough guy image. and they're the kind who are less likely to back down than they are to escalate. >> reporter: putin's also unpredictable. his invasion of ukraine, deployment of warplanes and ships to buzz nearby rivals indicate he could push this to a dangerous place. what could putin do to retaliate? analysts say he could use oil as a weapon. >> putin's next move is probably going to focus on the energy