The road isn't easy -- past shelling and eerie separatist checkpoints. But where it leads is harder still.

Twelve days after MH17 was blown out of the sky, pieces of the plane remain here, but for days investigators haven't been able to reach the site. On Wednesday, efforts to get to the bottom of the deadly crash hit another roadblock, as Ukrainian officials warned of possible landmines near the site.

The wreckage sits in tomb-like silence -- a monument to cruelty, to how 298 souls -- some shipped in parts, away on a separatist train -- have yet to find complete rest.

There are flowers and a teddy bear on the ground, where strangers have tried to mourn. The crash site still reeks of jet fuel and the stench of decay. Shrapnel holes are visible in the cockpit's remains.

In the hour a CNN team spent at the crash site Wednesday, there were no separatists, inspectors or Ukrainian soldiers there.

Just distant smoke that explains why the inspectors' large convoy has not, for the fourth day running, arrived.

Ukraine's National Security and Defense Council claimed Wednesday that "terrorists" -- the term it uses to describe rebels -- have set up firing positions and laid mines on the access road to the crash site of Malaysia Airlines Flight 17.

The Ukrainian government and pro-Russian rebels are fighting over control of eastern Ukraine.

Dutch investigators in Ukraine did not mention mines but announced Wednesday that unsafe conditions kept their contingent from visiting the crash site for the fourth straight day.

CNN could not independently confirm the veracity of the statement by the Ukrainian officials, though CNN's team traveled to and from the debris field safely Wednesday.

The dangers in the area make the work of international experts "impossible," the Ukrainian defense council said.

Workers with the Organization for Security and Co-operation in Europe made the same call and avoided traveling to the crash site Wednesday.

Ertrugrul Apakan, chief monitor of the OSCE Special Monitoring Mission to Ukraine, said he would like to see a cease-fire between combatants so investigators can work.

It was the fourth straight day the OSCE has joined the 50-strong team of Dutch and Australian investigators in declaring the region too dangerous to work in.

Dutch investigators have yet to lay eyes on the wreckage or the human remains believed still to be strewn across the huge debris field near the town of Torez.

CNN's team reported seeing three or four points of smoke from artillery fire. Because the area was militarized before the plane crash, it was not possible to know whether those firing positions were new.

Some human remains could still be found at the crash site, as well as belongings from the victims scattered about.

On the journey there, the CNN team -- which was traveling in just one car, as opposed to the convoy of dozens of vehicles that the investigators use -- saw only a small rebel presence on the road around the wreckage.

U.S. and Ukrainian officials have said that a Russian-made missile system was used to shoot down MH17 from rebel territory on July 17. Russia and the rebels have disputed the allegations and blamed Ukraine for the crash.

(CNN)