Ukrainian President Volodymyr Zelensky on Monday dismissed Ukraine's ambassador to the United States, Olga Stefanishyna, through a presidential decree, ending months of speculation over her departure following a government reshuffle in July.Stefanishyna, who had served as ambassador for nearly a year, said the decision to step down was her own and was "dictated by personal circumstances". (AFP)Stefanishyna, who had served as ambassador for nearly a year, said the decision to step down was her own and was "dictated by personal circumstances". In a Facebook post, she shared a letter requesting to be relieved of her duties and described serving as Ukraine's envoy to Washington as "the greatest honour" of her life.Also Read: Ukrainian Drone Attack Sparks Fire at Wildberries Warehouse in RussiaWhy was she dismissed?Her departure had been widely expected since Zelensky carried out a controversial government reshuffle in July, although the president's office has not publicly cited a reason for issuing the decree, news agency AFP reported.According to Ukrainian media reports, Stefanishyna is under investigation by the country's anti-corruption agency over allegations of wrongdoing. However, she has not been formally charged or accused of any offence, the report further added.The change comes at a time when Kyiv is lobbying Washington to secure more Patriot air defence systems as Russia intensifies its missile and drone attacks.As ambassador, Stefanishyna played a key role in managing ties with Ukraine's most important military ally. The position is central to coordinating US military assistance and intelligence cooperation during the war with Russia.Reflecting on her tenure, Stefanishyna said Ukraine had managed to expand American weapons supplies and sustain support even as "the political climate in Washington was shifting against us."Zelensky has not yet named Stefanishyna's successor as Ukraine's ambassador to the United States.US-Ukraine tiesStefanishyna, a former deputy prime minister and justice minister, was appointed ambassador in July last year.Her tenure coincided with a challenging phase in relations between Zelensky and US President Donald Trump, whose ties with the Ukrainian leader have at times been strained.Recently, Trump said the United States must be "very careful" about giving Ukraine a license to produce Patriot air defense missiles, which Kyiv says it needs to defend against Russian attacks."These weapons are incredible. We have to be very careful about letting somebody build them," Trump said at the Camp David presidential retreat in response to a question about allowing Ukraine to produce the missiles.Ukraine's President Volodymyr Zelensky met with Trump for just over an hour at the White House last week for talks that came as Kyiv and Moscow intensify long-range strikes after US-led diplomatic efforts to end the war stalled.(With inputs from AFP)