Russian humanitarian convoy going to Ukraine

OK that's interesting, so while Ukraine and most of the West accuses Russia of arming the separatists and fueling the war Putin thought to send a humanitarian convoy to help the population in the East. Lots of theories came spraying out of this: is this a Trojan horses convoy? Soldiers, weapon, ammunition? Only medicine and food supplies?

We've all seen on TVs that long line of white trucks (were they German MAN trucks?) driving slowly towards the Russian-Ukrainian border. The officials in Kiev were kind of outraged of this idea, accepting help from the enemy is not exactly what they need.

So once the trucks reach the border what will it happen? Assuming there are sectors of border controlled entirely by separatists (likely they are) the trucks will get in and unload their supply without problems. If Ukrainians try to prevent them and stop them by force they need to be very carefully not to offer the pretext for a future Russian military intervention.