Pompeo issued the ultimatum following a meeting with German Foreign Minister Heiko Maas on Friday, saying the decision on whether to allow Huawei equipment would have severe consequences, according to Reuters. His words came at the start of a five-day European tour: "They [Germany] will take their own sovereign decisions, [but we] will speak to them openly about the risks... and in the case of Huawei the concern is it is not possible to mitigate those anywhere inside of a 5G network," Pompeo said.

Germany, alongside the UK and France, has refused to budge amidst the ratcheting pressure from the US over worries that China's intelligence is using its next generation networks as "back door" for aggressive telecommunications eavesdropping.

Pompeo told the news conference further: "(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)."