"Officers of the peacekeeping contingent are inspecting all the vehicles passing through the observation posts: whether they are transporting explosives and weapons, or not", the ministry said in a statement.
Russian military police are also patrolling the whole road to Stepanakert, the capital of the self-proclaimed Republic of Artsakh.
The reopening of the road through the Lachin corridor allows local residents to transport various goods from Armenia to Nagorno-Karabakh and vice versa.
Last week, Yerevan and Baku agreed to a ceasefire in Nagorno-Karabakh, putting an end to the six-week war over the disputed area. The agreement resulted in the loss of most territories controlled by the Armenian-dominated Republic of Artsakh and envisions the deployment of 1,960 Russian peacekeepers to the region.
Follow our live feed to find out more