The size of the territory returned to Azerbaijan under a border delimitation agreement on Friday was 6.5sq km, Mustafayev said on Friday.
Armenia had said in April it would return the uninhabited villages to Azerbaijan, which both sides said was a milestone on the road towards a peace deal between Yerevan and Baku who have clashed for more than three decades.
The decision by Armenian Prime Minister Nikol Pashinyan to hand over the four villages has triggered protests at home, with demonstrators calling for him to step down over what they cast as a betrayal.
Pashinyan, in an address to the nation late on Friday, described at length how Armenians had long sought a homeland within a specific geographic area and how demarcating national borders was part of that process.
He said the aim of all Armenians was to act "so that a sovereign and democratic Armenia with demarcated borders becomes a national ideology and concept".
Azerbaijan's retaking by force of the entirety of its Nagorno-Karabakh region in September 2023, a move which sparked an exodus of ethnic Armenians living there, dealt a painful blow to Yerevan.
But it has also paved the way for an elusive deal by removing a long-running source of disagreement from the table.
Azerbaijan and Armenia still have other unresolved territorial disputes though, mostly focused on enclaves which the two sides want the other party to relinquish control of or provide access to.
