The Vatican website was inaccessible Wednesday evening, the Holy See press service said, in a suspected cyberattack that the Ukrainian ambassador blamed on Russia.

"Technical investigations were ongoing (at the end of the day) because of abnormal attempts to access the website," Vatican spokesman Matteo Bruni said.

On Wednesday afternoon, several Vatican sites were offline for several hours and the official website, vatican.va, was still inaccessible in the evening.

The suspected cyberattack came a day after Russia expressed "indignation" at comments by Pope Francis singling out the alleged role of Russian ethnic minorities in Moscow's war in Ukraine, news agencies reported Tuesday.

Pope Francis in an interview published Monday said some of the "cruellest" actors among Russia's ranks in Ukraine "are not of the Russian tradition", but minorities like "the Chechens, the Buryati and so on".

Ukrainian ambassador to the Vatican, Andrii Yurash, tweeted: "Russian terrorists reach today sites of City State Vatican: many online pages of different structures of Roman Curia have become inaccessible!"

"Russian hackers one more time demonstrate real face of Russian politics," he said in English, adding that the cyberattack was a likely "response on last important statements" made by the pope.