Putin doesn't want to escalate this much, an Invitation by the Ukraine for outside forces to secure the area would see the rebels melt away from that area.
rh200 -Not going to happen; inviting outside forces to secure the area would bring 40,000 Russian troops to the Ukraine border very quickly, Ukraine knows this -and so does everybody else.
The first things of interest are the examination of the wreckage by skilled investigators
lomapaseo -not going to happen anytime soon. A.) it is a war zone and B.) inasmuch as those in control of the zone are not being cooperative here it is very likely that such an investigation is not in their best interest.