The EU has accused China of “illegal” trade practices as it launched an official dispute on behalf of one of its smallest member states.
The row was sparked when Lithuania allowed Taiwan to open a de facto embassy there, angering Beijing which sees Taiwan as part of its territory.
China downgraded its diplomatic relations with Lithuania, but denies ordering a boycott of Lithuanian goods.
The EU has now taken the case to the World Trade Organisation.
European Trade Commissioner Valdis Dombrovskis said China was blocking Lithuanian imports and imports from other EU states, if they have components coming from Lithuania.