Add class on svg path element

In my project I have an SVG world map with different paths with different id's and one class of map-path. For each country click I want to add class on each path. My HTML is like this:

<svg viewBox="">
    <path id="map_1" class="map-path" ......>
    <path id="map_2" class="map-path" ......>
    <path id="map_3" class="map-path" ......>
    <path id="map_4" class="map-path" ......>
    <!-- more <path /> elements... -->
</svg>