European Union foreign ministers arriving at a meeting in Brussels say that there may be lessons to be drawn from the spat between Turkey and Germany on campaigning by officials from outside the 28-nation bloc.
Slovak Foreign Minister Miroslav Lajcak says that the controversy highlights the lack of European rules and standards on allowing rallies by politicians from non-member countries.
He says that "it's about time to start discussing it. I think there should be rules. I would be rather restrictive, because as we can see it has a huge damaging potential."
Diplomatic tensions have been rising in recent days amid Turkish plans to have government ministers to address rallies in Germany and the Netherlands in support of an upcoming constitutional referendum that would give President Recep Tayyip Erdogan new powers.