The US has asked NATO-member Turkey to host some of the radar defenses and to approve the proposal for an Europe-wide defense network. Turkey has hesitated, saying it doesn’t want the system explicitly to target its neighbor, Iran. Iran has also cautioned Turkey about the plans.

The deal on the missile shield could be sealed at a two-day NATO summit starting Friday in Portugal.

Turkey’s Anatolia news agency, quoting unnamed sources, said Thursday that discussion over who would command the radar system that would be deployed in Turkey are also underway.