does not update its position when changing its center

I’m trying to put a circle in the center of my map. I have the following :

<MapView.Circle
    center={{latitude: this.state.region.latitude, longitude: this.state.region.longitude}}
    radius=1000
    fillColor="rgba(0, 0, 0, 0.2)"
    strokeColor="rgba(0, 0, 0, 0.2)"/>

but the circle doesn’t change when I change region while my MapView has a onRegionChange method that sets the new region

onRegionChange = (region) => {
    this.setState({region: region});
}