A US candidate decisively beat her Russian rival to become the next head of the main UN technology agency on Thursday in an election seen as a test of how many countries are still siding with Moscow after its invasion of Ukraine.

Doreen Bogdan-Martin won the election to become Secretary-General of the International Telecommunication Union (ITU) - the UN body that sets standards for new technologies - with 139 votes out of 172, defeating Russia's Rashid Ismailov.

In a sign of the significance of her campaign to Washington, US Secretary of State Anton Blinken wrote an endorsement in her brochure.

"I've worked for this moment for more than three decades," Bogdan-Martin said after her win in the secret ballot held in Bucharest.

The ITU veteran pledged to improve digital connectivity and use technology to address challenges such as the climate crisis, food security and the gender divide.

"It's a symbolically very important election," Olaf Wientzek, director of the Geneva office of the German Konrad Adenauer Foundation, said. "It's a way to measure how many countries are still siding with Russia," he added, describing the outcome as a "heavy defeat" for Moscow.

Ismailov, who has held posts at Huawei and Nokia as well as Russian government roles, ran on a commitment to make technology more “human-centric” and to bridge digital divides.

A Russian mission spokesperson was not immediately available for comment.

Some observers had depicted the vote as a battle over the future control of the internet, between open standards and countries seeking to step up controls over communications.

"It's a good storyline but not really realistic. The Secretary-General doesn't determine policy," ITU Deputy SG Malcolm Johnson told Reuters.

He said the agency's 193 member states made the high-level decisions while most of the standardisation work was done by private sector members.

Bogdan-Martin is the first woman to head the Geneva-based agency which allocates global radio spectrum and satellite orbits and sets standards for artificial intelligence and other new technologies.

Diplomats said the voting for the top post and other positions took place amid an unusually high level of lobbying and campaigning.

- Reuters