BERLIN (Reuters) - The United States raised the pressure on Western allies in a war of attrition over next-generation networks on Friday, saying countries that allow China’s Huawei to build their telecoms infrastructure could be cut off from crucial intelligence data.

Secretary of State Mike Pompeo issued the warning after meeting Foreign Minister Heiko Maas of Germany, which has so far stood with Britain and France in declining calls to ban the state-owned manufacturer from the 5G networks now being built.

In the latest sign of escalating trans-Atlantic tensions over trade and security, Pompeo, on the first leg of a five-day European tour, said that while countries would take a “sovereign decision” on which equipment to use, that decision would have consequences.

“(There is) a risk we will have to change our behavior in light of the fact that we can’t permit data on private citizens or data on national security to go across networks that we don’t have confidence (in),” he told a news conference.

Pompeo later met Chancellor Angela Merkel for brief talks before flying on to Switzerland, describing Germany as “a great, important partner and ally of the United States”.

Merkel herself had just flown back from the United States the night before after delivering a speech to graduating Harvard students in which she exhorted them to “tear down walls of ignorance” and to stand for truth over lies - words widely interpreted as veiled criticism of U.S. President Donald Trump.

“The U.S. is and remains our most important partner outside Europe,” Merkel told reporters ahead of the meeting. “We have many issues to discuss, since the world is not at rest,” she added, mentioning the challenge of preventing Iran from acquiring nuclear weapons and hindering Iran’s “aggressive actions”.

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Pompeo urged close ally Britain this month not to use Huawei’s technology to build new 5G networks because of concerns it could be a vehicle for Chinese spying.

A Chinese Foreign Ministry spokesman, responding to similar comments on Huawei made by U.S. Vice President Mike Pence in Canada on Thursday, said the United States had yet to prove that Huawei’s products presented a security risk.

“We hope that the United States can stop these mistaken actions which are not at all commensurate with their status and position as a big country,” said spokesman Geng Shuang.

The United States is at odds with its German allies on a host of issues, from trade to military spending and nuclear non-proliferation.

IRAN AGREEMENT

Pompeo’s visit had been scheduled earlier this month, but was called off at the last minute as tensions rose over Iran. Berlin and Washington differ on the best approach to Iran over its nuclear program.

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Under a 2015 nuclear agreement with major powers, which Washington withdrew from last year, Tehran accepted curbs on its uranium enrichment program in exchange for the removal of most international sanctions.

Iran’s decision this month to backtrack from some commitments under the accord - in response to U.S. measures to cripple its economy - threatens to unravel the deal.

The German Foreign Ministry said on its website: “Germany and the U.S. agree: For the security of the region, it is crucial that Iran does not come into possession of nuclear weapons.”

Maas stressed during his talks with Pompeo that “as long as Tehran adheres to the agreed rules, the agreement makes the region safer,” the ministry added. A German envoy seeking to preserve the nuclear deal visited Iran last week.

But in comments on Iran in an interview to run in German daily Bild on Saturday, Pompeo said: “We hope Germany does more ... The (Iranian) regime is an expansionist theocracy. Free democracies have a duty to protect the world from this threat.”

Pompeo also took a swipe at the German government for failing to reach a NATO target of spending 2% of national income on defense, telling Bild: “The most serious consequence is in the hands of the German population.”

“The federal government has given the promise of 2% and the people should demand that the government keeps its promise,” he said in usually blunt comments towards a NATO ally.