According to Xoán Mao, in addition to Gondomar and Amarante, both from the district of Porto, the other two new members are the Deputación Provincial de Ourense and Ponteareas, from Galicia.
The four new members will join in February 2021 at the General Assembly of the Atlantic Axis.
"The Axis continues to grow, it is a sign that we are doing a good job," said Xoán Mao.
The Atlantic Axis currently has 35 municipalities in northern Portugal and Galicia.
For 2021, it has a budget of more than €3.9 million.