Vice President Mike Pence and Polish Prime Minister Mateusz Morawiecki signed the deal in Warsaw, where Pence is filling in for President Donald Trump, who scrapped his trip at the last minute because of Hurricane Dorian.
The signing comes amid a global battle between the U.S. and Huawei, the world's biggest maker of network infrastructure equipment, over network security.
The agreement endorses the principles developed by cybersecurity officials from dozens of countries at a summit in Prague earlier this year to counter threats and ensure the safety of next generation mobile networks.