Each of the three countries has maintained its own trade mark registry, but that of Russia has attracted the registration of far more trade marks than the other two countries. Now that trade barriers are being dismantled, goods bearing trade marks which are registered in Russia, but not in Belarus or Kazakhstan, might freely enter union territory from neighbouring territories, such as Poland in the west and China in the east.  As the author observes: 

Belarus and Kazakhstan do have their own IP registers for customs control purposes, but these registers contain far fewer entries than their Russian equivalent. In any event, whatever the effectiveness of the border measures in Belarus and Kazakhstan, they will be entirely inapplicable in respect of trade marks not registered there. Thus, it is vital for trademark owners to protect their trade marks in all three countries through either national or international registration procedures.