US takes aim at EU's Russia pipeline and China trade pact

"We will continue to monitor activity to complete and certify the pipeline, and if that activity takes place, we'll make a determination on the applicability of sanctions," he added.

Blinken's symbolic first trip to Europe since taking office was meant to put ties with the new US administration on a friendly footing.

Russia's pipeline to Germany is almost complete and Berlin is lobbying Washington to let it go ahead.

But despite the US-EU reset, Blinken told German foreign minister Heiko Maas there was "no ambiguity" on US opposition when they met in the margins of a Nato meeting on Tuesday.

"Nord Stream 2 is a bad idea and I reiterated that view directly to foreign minister Heiko Maas and I also made clear that firms engaged in pipeline-construction risk US sanctions," Blinken said.

Blinken designated Russia and China as Nato's biggest threats.

"Beijing's military ambitions are growing by the year," in the Pacific, he warned.

Russia was building up forces in the High North, the Baltic Sea, and the Mediterranean, waging war in Ukraine, and poisoning people with chemical weapons, he added.

And both were "using access to critical resources, markets, and technologies to pressure our allies and drive wedges between us", Blinken said.

He did not mention the CAI by name.

But he urged the European Parliament to "stand firm" against Chinese "bullying", ahead of its vote, later this year, on ratifying the accord.

Blinken spoke after China imposed sanctions on MEPs in retaliation at Western ones on Chinese human-rights abusers.

"The retaliatory sanctions against the European Parliament ... make it all the more important that we stand firm and stand together, or else risk sending the message that bullying works," he said.

Blinken and EU foreign affairs chief Josep Borrell re-launched a "bilateral dialogue" on China, to discuss the "full range of related challenges and opportunities" on Wednesday.

"The United States won't force our allies into an 'us or them' choice with China," Blinken noted.

But he envisaged EU states working with China in limited areas, such as "climate change and health security" only.

Turbulence

Blinken's visit came amid turbulent times in EU-Russia and China relations.

Russia ties were put on knife-edge over its poisoning and jailing of opposition leader Alexei Navalny, who warned, also on Wednesday, that his health had badly deteriorated while in detention.

The Chinese dispute blew up over China's persecution of the Uighur minority in its Xinjiang province.

The German government has clung to Nord Stream 2, despite rising political opposition at home.

But Blinken is under pressure in Washington to torpedo the project, even if he had wanted to make nice in Brussels.

"This pipeline must be stopped and your leadership is required towards that end," two senior Democratic senators, Bob Menendez and Jeanne Shaheen, urged Blinken in a letter on Tuesday.

"Nord Stream 2 sanctions packages [must] be accelerated to meet the urgency of the moment," they said.

A Russian ship is currently laying the last few kilometres of the pipeline in the Baltic Sea.

But Nord Stream 2 also needs other business services to function and US sanctions have already prompted Norwegian certification company DNV GL and insurers Zurich Insurance and Munich Re, among 16 other firms, to walk away.

Meanwhile, China's health minister, Huang Runqiu, held video-talks on climate change with EU officials, including European Commission vice president Frans Timmermans, some EU states, and the US on Tuesday as if there was no diplomatic crisis.

Red line?

But if Beijing wanted to dial down tension, then taking back its sanctions on MEPs and their families, who were also blacklisted, could be a red line for the investment treaty.

"What I hope is that diplomacy will find a way of de-escalating ... We need to build some trust, for the moment there is none between the parties," Iuliu Winkler, a Romanian MEP from the centre-right 'EPP' group, the largest one in the EU Parliament, told the Financial Times newspaper on Wednesday.

"There has to be a solution of these sanctions before we come back to ordinary business on this," Bernd Lange, a German MEP from the centre-left 'S&D' group, the second largest, also said.

And even the Commission's pro-business vice president Valdis Dombrovskis called China's sanctions "unacceptable".

"The prospects for the CAI's ratification will depend on how the situation evolves," he told press in Brussels on Wednesday.