SCOTT SIMON, HOST:

It's been a year since a Malaysian jetliner was shot down over eastern Ukraine, killing all 298 people on board. Western governments believe that flight MH17 was hit by a Russian surface-to-air missile, but there is still no official determination of who was responsible. That's in part because pro-Russian separatist groups in eastern Ukraine have blocked investigators from gathering evidence. Meanwhile, there has been a spike in fighting in the embattled region, though a tenuous cease-fire seems to be holding. We're joined now in our studios by Michael Bociurkiw. He is with the special monitoring mission to Ukraine with the Organization for Security and Co-operation in Europe, also known as the OSCE. Thanks very much for being with us.

MICHAEL BOCIURKIW: Pleasure.

SIMON: What's the current status of the investigation?

BOCIURKIW: Well, the current status - it's a Dutch-led investigation, as you know. And our role, of course, since day one, has been to facilitate access for them. Now the work, unfortunately and sadly, was suspended near the end of June because when it came to crossing over to Luhansk Oblast, which is under the control of the rebels, they weren't allowed in.

SIMON: So the quick answer is the investigation can't be completed because of interruption on the ground.

BOCIURKIW: For the time being. We are hopeful that we can continue to facilitate access but we have good days and we have bad days when it comes to helping to facilitate access.

SIMON: And a year ago, who had weapons and who were using them?

BOCIURKIW: A year ago, on July 17, you had an accumulation of heavy weaponry. At that time, we were reporting, for example, the existence of MANPADS, these mobile shoulder missile-firing systems. So there was, indeed, a buildup of weaponry. Remember that this conflict started with little green men coming into that part of eastern Ukraine.

SIMON: Little green men meaning Russian paramilitary.

BOCIURKIW: Well, you had guys without insignia, in uniform, carrying light weaponry.

SIMON: We should explain - a number of news organizations have identified them through conversations with some of the soldiers as Russian.

BOCIURKIW: And I can tell you that in the past month or two we have, with our own eyes, seen at least four individuals with a Russian Armed Forces insignia on them.

SIMON: What's life like in the region you're describing? We - more than 2 million people have had to leave their homes in the fighting.

BOCIURKIW: I wish, by this time, I had better news. Our colleagues in the U.N. system are now reporting that at least 2.3 million people have been uprooted. Officially, there are 1.2 million internally displaced. And don't forget that a year ago, there were no displaced people and now Ukraine is in the top 10 countries in the world with large displaced populations. We can tell you also that the humanitarian situation is very dire. Well over 6,000 - almost 7,000 - people have been killed and almost 17,000 have been injured. There's very little water, food, medical supplies available, so life is very, very difficult. But the problem for Ukraine, of course, is it's been well over a year now that the conflict has been active, so you can imagine the strain on the system and on society's fabric.

SIMON: Ukraine says that Russian humanitarian convoys are carrying weapons across the border.

BOCIURKIW: We have no way to verify that but what we do observe - we have a sister border monitoring mission on the Russian side of the border and they do report when these convoys cross - what time, how many vehicles, whether they're inspected. But I can't recall one time where we've actually reported that we've seen arms or anything like that. But I do have to point out is that we're not able to enter these vehicles.

SIMON: Is this frustrating work, Mr. Bociurkiw?

BOCIURKIW: The biggest frustration for us right now is access. There have been many close calls - of shelling landing very near to our vehicles, we're facing long delays at checkpoints, heavy weaponry - and I must point out, it's from both sides - has not been properly stored - it's been moved, it's been put back into use. So it is turning into this sort of frozen conflict where you can't really see an immediate end.

SIMON: What's the point of a monitoring mission? I think a lot of people might wonder if...

BOCIURKIW: Sure.

SIMON: If heavy weaponry is crossing the borders anyway, if you can't get an international investigation properly accomplished because you are denied access. What's the point of having monitors on the ground?

BOCIURKIW: Think of it as the eyes and ears of international community on the ground and also this very, very important role of facilitation of access. For example, the experts that are dealing with the MH17 disaster, for repair crews, for humanitarian aid, our mission over the course of more than a year has been able to establish very good contacts with all sides, hence we - we're, you know, a trusted body that can go in and report. And without that information, it would be very difficult, I think, for the international community to figure out what is going on on the ground in Ukraine.

SIMON: Michael Bociurkiw is the spokesperson for the OSCE's special monitoring mission to Ukraine. Thanks very much for being with us.