"The Russian border guards used a dog to check some of the cargo trucks. Ukrainian officers – 7 border guards and 4 customs officers – were present on site and divided in three teams on each of the aforementioned lines. They performed visual observation of the opened trucks from the outside," the OSCE said in its Thursday report.
The convoy then headed for Donbas and returned later in the day.
"The backdoors of the trucks were open and both Russian and Ukrainian officers quickly checked the trailers," the OSCE said, adding that after the empty vehicles were inspected, all 83 of them crossed back into the Russian Federation.
On Wednesday, a Russian Emergencies Ministry official told RIA Novosti that Russian humanitarian aid trucks had delivered over 1,800 metric tons of food and daily essentials to the Donbas self-proclaimed people's republics of Donetsk and Luhansk (DPR and LPR).
The regions have been suffering from a severe humanitarian crisis since Kiev launched a military operation against local independence supporters in April, 2014. Thousands of people have lost their homes and crucial infrastructure has been damaged in Donbas.
Since August 2014, Russia has sent over 20,000 tons of food, water, clothes, medicine, power generators and building materials to the Donetsk and Luhansk self-proclaimed republics.
