What is inside wagons of Russian "humanitary convoys"

 Starting from August 2014, Russia is sending huge "humanitarian convoys" to Donbass region. These convoys consist of huge white wagons. No one inspect what is inside them when they cross the Ukrainian boundary which is not controlled by the government.  There is a strong opinion that Russia uses these convoys to deliver weapons and military equipment to occupied territories.

26 February, Viktoria Nuland, an Assistant Secretary of State for European and Eurasian Affairs at the US Department of State, said in an interview to Meduza news agency that  the Russian "humanitarian aid" sent to Donbass region  apparently consists of fuel for tanks and gear for soldiers.
https://www.charter97.org/en/news/2014/11/26/128039/

Here are several photo and video documents which support her statement.

A recent video recorded 22 November in Donetsk. It is a record of a surveillance camera showing a street of Donetsk.
One can see on this video that a great white wagon from "humanitary convoys" rides the street and it is
followed by two big guns:

Another video from 17 November shows unloading of a white wagon of seventh convoy from Russia. At 1.01 one can  see big tires and at 1.18 some radar equipment.

Next video from 11 September (the second "humanitary convoy") shows what is inside white wagons of convoys. A military car at 0.37 and green military boxes at 0.58:

Two more photos showing what is inside white wagons of "humanitary convoys":

There are also many different reports of witnesses saying that convoys deliver projectiles for multiple launch rocket systems. One such a recent report came from an activist Dmitro Snegirev who refers to witnesses in Luhansk. Reference in Russian:
http://www.unian.net/politics/1010961-v-luganske-gumkonvoy-rf-vyigruzil-na-trikotajnoy-fabrike-snaryadyi-dlya-grada-aktivist.html