LAS VEGAS, Nev., Aug 11 (Reuters) - Ukraine's top cyber official addressed a room full of security experts at a hackers' convention following a two-day trip from the capital, Kyiv, to a golden casino in Las Vegas.

During his unannounced visit, Victor Zhora, the deputy head of Ukraine's State Special Communications Service, told the so-called Black Hat convention on Wednesday that the number of cyber incidents to have hit Ukraine tripled in the months following Russia’s invasion of his country in late February.

"This is perhaps the biggest challenge since World War Two for the world, and it continues to be completely new in cyberspace," Zhora told an audience at the annual conference.

Ukraine faced a number of "huge incidents" in cyberspace from the end of March to the beginning of April, Zhora said, including the discovery of the "Industroyer2" malware which could manipulate equipment in electrical utilities to control the flow of power.

Russian hackers also hit Ukraine at the onset of the war though a cyberattack that took down regional satellite internet service.

Since the beginning of the year, Ukraine had detected over 1,600 "major cyber incidents", Zhora said.

Zhora told Reuters in an interview that Microsoft, Amazon and Google had offered pro bono cloud computing services to the Ukrainian government as it moves its data out of the country, away from the destruction wreaked by Russian bombs and missiles.

Some of Ukraine's data archives are being held within data centers across "multiple countries," he added, without elaborating.

Zhora said his trip to Las Vegas took two days. He traveled to neighboring Poland to stay a night before flying to the United States.

Zhora said he would not waste time on the slot machines at the sprawling Mandalay Bay casino, where the Black Hat conference is being held: "It would be inappropriate for me to gamble here while Ukrainian soldiers are defending our land." (Reporting by James Pearson; additional reporting by Christopher Bing; editing by Grant McCool)