There is a stark divide between where the United States and its NATO allies and European Union partners stand when it comes to considering a Chinese company to provide 5G ultra-wideband communications.

The EU “is not sure China is a rival,” one of its top diplomats said speaking at the Foreign Policy Defense Forum Thursday. At the same event, senior Pentagon officials warned every country to be extremely careful when it comes to making this decision because it means their future security.

“The threat assessment is not identical” when it comes down to examining Huawei as the 5G provider and potential danger. The Chinese telecommunications giant, the recognized leader in these areas, appears to be the preferred partner for nations from Iceland to the United Kingdom and onto the continent. Huawei is also aggressively selling its services into Africa, said Diego de Ojeda, the European Commission Representative to the Political and Security Committee of the European Union.

Nations negotiating with China over 5G “need to have your eyes wide open” before signing any contracts, said Army Maj. Gen. William Hickman, director of strategic plans and policy at NATO’s allied command transformation, while speaking on the same panel with Ojeda. Andrew Winternitz, acting deputy assistant secretary of defense for European and NATO policy, added, “demand nothing less than having robust, secure networks.”

The message from the Americans to Europe was to make smart choices because these decisions have a direct impact on command and control of military operations.

For almost two years, lawmakers on Capitol Hill have questioned the close links between Huawei and the Chinese government create the potential for espionage and sabotage. Recently, the White House banned Huawei components from being used on government networks. The administration also moved to limit the company’s access to the American market in areas other than 5G.

Those actions prompted Ojeda to warn the United States about taking “unilateral steps” when it comes to 5G and Huawei and further dividing it from its partners in the EU.

However, while the NATO and the EU are at odds with the United States over telecommunications security, they appear to be in alignment over what to do about Turkey if Ankara buys the Russian S-400 air defense system.

That buy possesses “unacceptable risks for the United States,” Winternitz said. “There are no measures that can mitigate” the United States’ and NATO’s opposition to the move that would install a system that is not interoperable with the alliance’s systems. It puts at risk the advantages the F-35s pose to Kremlin’s defense in the event of a conflict. He called the decision “incompatible with Turkey’s commitment to NATO.”

Never far from the discussion at the event was how NATO and the EU changed their thinking about security in Europe following Russia’s heavy-handed moves in Crimea and its outright military support for Ukrainian separatists in 2014.

“I think we’ve all grown up in the last ten years,” Winternitz said.

Ojeda said, “there are lots of things NATO cannot do without the EU” and vice versa, but the most significant area to work on in the decade has been acting to deter Russian territorial ambitions.

Recognizing the threat from Moscow and committing to continental security “is a massive change in culture for EU.” Before Crimea and the fighting in eastern Ukraine, “defense was a no-go” in EU diplomatic discussion. Now, “everybody is asking us to be more active,” Ojeda said

To improve mobility of forces in a crisis, Ojeda said the 28 EU nations approved $6.5 billion to standardize the width of bridges and improve ports, rail and highway infrastructure. He added each of the countries will match their contribution to the union providing $13 billion for these dual-use improvements.

NATO members are working to standardize customs forms with the EU and re-looking at host nation agreements as forces rotate in and out of front-line countries bordering Russia, Winternitz added.

The “two strong alliances .. are complementary” in “developing fields of responses” to the “dark side threats” just below active warfare, said Johann Schmid, director of strategy and defense at the newly established EU center in Helsinki to counter hybrid threats.

Russian attempts to change election outcomes on the continent and the United States, spread fake news and propaganda to change public opinion through social media, and destroy the trust between governments and its citizens highlighted gaps between the Russian threat and existing defenses, he said.

“Ukraine was the catalyst” for the coming together of alliance and union interests.