Romania has summoned the Swiss ambassador to Bucharest over allegedly discriminatory political posters.
The rightwing Swiss People's Party is campaigning with posters showing black ravens pecking at Switzerland to warn against an influx of migrants if voters approve a labour accord with the European Union in next month's nationwide ballot.
The Swiss ambassador, Livio Hürzeler, said Bucharest had called on the Swiss government to condemn the campaign.
He said he had explained the position of the Swiss government and the democratic right to freedom of expression.
The People's Party has rejected any interference by foreign states as inappropriate.
Voters will decide on the continuation of the labour accord with 25 EU member states, granting access to the labour markets, and its extension of Bulgaria and Romania, on Februrary 8.