Russia's 23rd so-called 'humanitarian' convoy has entered Ukraine illegally, without being inspected by a Ukrainian interagency group.

"In the morning of April 2, the Russians unilaterally carried out the customs clearance of the next, twenty-third, so-called 'humanitarian' convoy," the press service of Ukraine's State Border Guard Service reported on Thursday.

As the convoy flagrantly violating international and national legislation and procedures agreed with the International Committee of the Red Cross, the Ukrainian interagency group was only able to visually observe the cargo without inspecting it, the border service said.

Two columns of the 'humanitarian' convoy consisting of 124 trucks crossed the Donetsk (Russia) and Matveyev Kurgan (Russia) border checkpoints between 07.30 to 08.25 Kyiv time on Thursday.

"The major difference of Russia's twenty-third 'humanitarian' convoy is the fact that it contains dangerous substances, namely herbicides (six trucks), and non-humanitarian cargo, i.e. foaming agents (three trucks), and steel (one truck)," the border service said.