The EU's trade and investment relationship with China is "not sustainable", the European Commission said on Friday, vowing a stronger response as commissioners discussed how best to shield Europe's industries from surging Chinese imports. Commissioners were pitching ideas ahead of an EU leaders' summit on June 18 to 19, and possible proposals could include forcing EU firms to diversify supply chains or introducing new trade mechanisms to curb China's access to the EU market in chemicals, metals and clean energy technology.