Almost certainly nothing. Russia is too powerful. The Russian government will deny it and put some story out through its propaganda outlets. Governments of other countries will say Russia did a bad thing. Maybe a few low-level diplomats will be sent home so some governments can be seen to be Doing Something. Things will carry on as normal...unless Russia goes so far so fast so openly that war can't be avoided. Which I think very unlikely - Putin is too skilled a politician for that.