SIMIC

Three of the four biggest parties have already said that they cannot support the deal until sanctions are lifted, while some factions of the European People's Party (EPP) - Europe's biggest party - are asking support to be withheld.

The deal requires ratification by the European Parliament - a process slated to begin next year - before it can be signed into effect.

"Generally as long as our elected officials are sanctioned by a third state, we can't pursue any agreement with said state," said one source familiar with internal dynamics.

EU Trade Commissioner Valdis Dombrovskis had previously been quoted by London's Financial Times saying that "the ratification process cannot be separated from the evolving dynamics of the wider EU-China relationship".