Chinese telecom giant Huawei on Wednesday won a contract to supply 5G infrastructure in Germany but the politically sensitive deal is subject to government approval following US concerns about snooping.
Telefonica Germany, the second biggest operator after Deutsche Telekom, said it was giving Huawei and Finland's Nokia an equal role in the project, calling the two companies "proven strategic partners".
"This cooperation... will be subject to successful security certification of the technology and the companies in accordance with the legal regulations in Germany," Telefonica Germany said in a statement.
The company, a unit of Spanish giant Telefonica, said it was "thus responding to the ongoing political process of defining these security guidelines without delaying the start of the 5G roll-out".
It said it would begin the 5G upgrade next year and was hoping to supply 30 cities by the end of 2022.
The US and other international powers have voiced concerns that Huawei could be used by Beijing for spying - a claim the company strenuously denies.
Germany has so far defied pressure to exclude Huawei from taking part in the bidding process, insisting that it would set stringent security conditions.
But critics have accused Berlin of trying to appease China, its largest trading partner, and putting economic interests first.
Last month, Economy Minister Peter Altmaier sparked US anger by drawing a parallel between alleged Chinese and US snooping as part of the debate.
Altmaier referred to the allegations that began emerging in 2013 of US spying on German soil.
Even so, he said: "We didn't boycott them".
Altmaier also pointed out that the US required its own telecoms companies to provide information "that is necessary in the fight against terrorism".
US Ambassador Richard Grenell said there was "no moral equivalency between China and the United States".