Ursula von der Leyns was booed in Bulgaria after arriving in the city of Varna.
The purpose of the visit by one of the leading representatives of the so-called "war party" in Europe was to take part in what were described as talks about security in the Black Sea.
Demonstrators greeted the president of the European Commission with signs:
"Verna wants peace! ".
"Peace, not war! ".
"Ursula belongs in prison! ".