U.S. President Donald Trump and European Commission President Jean-Claude Juncker chat on the second day of the G20 summit in Hamburg | Sean Gallup/Getty Images EU looks to water down impact of US sanctions on Russia But the fight isn’t over.

Brussels is sounding complaints about America's latest sanctions on Russia, but behind the scenes it's already blunted some of their impact on Europe.

Commission President Jean-Claude Juncker warned Wednesday that the EU is ready “to act swiftly” and “within a matter of days” if the proposed sanctions package against Russia going through Congress this week hurt the EU’s energy security. “America First cannot mean that Europe’s interests come last,” Juncker said. His tough talk was preceded by an internal note Juncker’s cabinet sent to EU commissioners that surfaced over the weekend, also highlighting his concerns.

Before Juncker started making tough public statements, however, EU civil servants lobbying in Washington managed to tone down the initial scope of the proposed sanctions through last-minute amendments agreed to over the weekend, according to officials in Brussels and Washington.

"We've been in close touch over the past five weeks with the EU delegation in Washington and the embassies,” a Senate Democratic aide said on condition of anonymity.

And in the run up to Tuesday's House vote, the EU managed to “directly” add language to the amended text that calls on the U.S. president to uphold unity with European partners through the implementation of the sanctions, according to the Senate aide.

“It’s critically important that we stand shoulder-to-shoulder with our European allies in countering Russian aggression,” House Foreign Affairs Chairman Ed Royce, a Republican from California, said about the revised bill’s attempts to address EU worries. “That’s why, in the bipartisan House-Senate negotiations, we secured important changes to improve transatlantic cooperation.”

An earlier version of the bill would have triggered sanctions even if Russian companies had a very small level of participation in joint projects with European companies.

The House voted 419-3 in favor of that version of the bill, which also includes sanctions on Iran and North Korea.

“We do a lot under the radar because we wanted to avoid the appearance that we are split with the U.S. on the sanctions,” a Commission official said. The Commission decided to up the ante publicly this week anyway because “now the pressure was too high … and we didn’t like the [original] scope of the proposed measures,” the official said.

And to be sure, the fight isn't over: The Senate must pass the bill too. House and Senate Republicans moved toward resolving a dispute late Wednesday over portions of the measure that deal with North Korea, allaying concerns that it might be stalled. The White House has avoided taking a firm position on the bill.

The draft U.S. sanctions law would target Russian energy, financial, railways, shipping and metals and mining sectors — but it’s the energy sector that worries the Commission most. It could deliver an economic blow to EU companies involved in Russian energy export pipelines or that partner with Russian companies on energy projects, and could take a toll on the bloc’s energy diversification efforts.

An earlier version of the bill would have triggered sanctions even if Russian companies had a very small level of participation in joint projects with European companies. That would have threatened projects the EU sees as crucial for its energy diversification, such as Azerbaijan’s Shah Deniz 2 gas field, which the U.K.’s BP operates and Russia’s Lukoil has a 10 percent stake in, and Egypt’s offshore Zohr gas field, which Italy’s Eni operates and Russia’s Rosneft owns a 30 percent share of.

But the EU managed to raise the threshold so sanctions only kick in if Russian stakeholders have a participation of 33 percent or more, the Senate aide said. That knocked Shah Deniz and Zohr off the list.

Republican and Democratic negotiators also made two key changes to the bill in response to European concerns with the bill’s pipeline-related sanctions. One alteration is designed to ensure allies would be consulted before any penalties are imposed that could hurt German access to natural gas from Russia. Another tweak aims to make clear that the sanctions would not indirectly impede a Kazakhstan-originated oil pipeline project.

Despite the softer tone of the proposed sanctions, many projects and companies could suffer.

"The Germans have had a lot of interventions on the Hill," an EU official said.

While a number of its concerns “are being taken into account,” the Commission also said “the U.S. bill could have unintended unilateral effects that impact the EU’s energy security interests.”

Despite the softer tone of the proposed sanctions, many projects and companies could suffer.

One worry is also that European energy or services companies involved in maintaining, repairing, or expanding pipelines in Russia could also be affected, which would also include the upgrade of pipelines in Russia that feed the Ukrainian gas transit system — a crucial route of gas delivery for the EU.

Other projects that could be affected are: the existing Nord Stream 1 gas pipeline that delivers Russian gas to Germany; the planned Baltic liquefied natural gas import terminal, for which Shell agreed to set up a joint venture with Gazprom in June; and the Blue Stream gas export pipeline to Turkey, where Eni has a 50 percent share.

The planned Nord Stream 2 pipeline, which initially many interpreted to be the target of the proposed sanctions, could also still be affected.

Elana Schor contributed reporting from Washington.

This article has been updated to include the latest on negotiations between House and Senate Republicans over the sanctions bill.