The trip — not reported at the time — comes as Kyiv’s brigades pursue a counter-offensive in their nation’s east and south against Russian forces, launched earlier this month after weeks of anticipation.

During his trip Burns reaffirmed “the US commitment to sharing intelligence to help Ukraine defend against Russian aggression,” the US official said.

According to The Washington Post, which first reported the visit, Ukrainian officials shared plans to claw back Russian-occupied territory and begin ceasefire negotiations by the end of the year.

Burns “travelled to Ukraine as he has done regularly since the beginning of Russia’s recent aggression more than a year ago,” the US official said. The Post reported that the visit occurred in June.

The trip took place before the 24-hour insurrection by the leader of the Wagner private military company, Yevgeny Prigozhin, according to the official.

The mutiny, which was widely seen as the biggest threat to Kremlin authority in decades, “was not a topic of discussion,” the official added.

Washington has attempted to make clear to Russia it played no role in the rebellion, with major US media reporting Friday that Burns called the head of Russia’s SVR foreign intelligence service, Sergei Naryshkin, following the uprising to assert that the US was not involved.

The Ukrainian military’s commander-in-chief Valery Zaluzhny has said his country’s counter-offensive plans are being hobbled by the lack of adequate firepower, from modern fighter jets to artillery ammunition.

On Tuesday the US announced a fresh US$500 million package of arms to bolster the counter-offensive, including armoured vehicles, precision munitions and mine-clearing equipment.