President Volodymyr Zelensky announced on Sunday a shake-up of his top leadership, including the dismissal of the prime minister, in a personnel overhaul that comes as momentum in the war has shifted in Ukraine’s favor.

Mr. Zelensky said the personnel changes were needed to focus the government’s work on high-priority foreign and domestic policies, including relations with the United States, membership talks with the European Union, securing sufficient supplies of weaponry for the army, and supporting cities and towns near the front line.

“Ukraine is changing its political strategy,” Mr. Zelensky said in a statement about the overhaul. He said he would designate an official to oversee each priority policy.

Mr. Zelensky said that Prime Minister Yuliia Svyrydenko, a 40-year-old former minister of economy who had led a team of mostly young politicians in Mr. Zelensky’s government, would step down as prime minister.

“The Cabinet of Ministers needs to be renewed,” Mr. Zelensky said.

In the statement, he did not mention any other personnel changes. Earlier, Mr. Zelensky had said he planned changes in the diplomatic service in order to focus diplomacy on securing military supplies from allies. In the statement, he said he would also replace leaders of law enforcement agencies.

Political analysts will be watching two popular generals seen as potential rivals for the presidency in postwar elections, both of whom now work in Mr. Zelensky’s administration.

General Kyrylo Budanov, a former director of military intelligence, is currently chief of staff, and General Valery Zaluzhny is ambassador to Britain. Whether Mr. Zelensky keeps them inside the administration, and in which capacity, will partly define Ukraine’s postwar political lineup.

Mr. Zelensky said he would work with Parliament, which must approve ministerial changes, on the overhaul. Mr. Zelensky’s political party, Servant of the People, holds a majority in Parliament but has sometimes struggled to pass legislation or win confirmations, as lawmakers don’t always vote along party lines.

Mr. Zelensky last reshuffled the cabinet in July 2025, after a year and a half of gradual losses along the front line and as Ukraine suffered electrical blackouts as Russia hammered the country’s power grid.

He has replaced individual ministers in scandals over mismanagement and corruption, including a minister of national unity and minister of energy who were implicated by anti-corruption investigators in a kickback scheme.

The current political reshuffle comes after a shift in the tide in the war. Ukraine’s strategy of fighting with drones both on the front line and to hit targets deep in Russia is yielding results.

The Russian army is enduring huge casualties from exploding drones. U.S. and Ukrainian officials estimate about 30,000 of its soldiers a month are killed or injured just to maintain a mostly static front line. Russia is making slow gains in the eastern Donbas region but some months has a net loss of territory as Ukraine advances elsewhere.

Ukraine is also mass producing long-range exploding drones that have incapacitated about a quarter of Russia’s oil refining capacity. Ukraine claimed to have struck more than 90 ships in the Sea of Azov in the past week, in what would be a major security lapse for Russia in the sea.

Stas Kozliuk contributed reporting from Kyiv, Ukraine.

Fidji Simo, who served as second in command to OpenAI’s chief executive, Sam Altman, before taking a medical leave in April, said on Thursday that she would not return to the job.

“Today, I shared with the OpenAI team that I have decided to leave my full-time role at OpenAI and transition to being a part-time advisor,” she said in a post to social media.

Ms. Simo joined OpenAI’s board of directors in March 2024, while serving as chief executive of the grocery delivery company Instacart. A year later, she left Instacart to become OpenAI’s first chief executive of applications, charged with overseeing the company’s engineering, product and business teams.

Her title was later changed to chief executive of A.G.I. deployment, referring to artificial general intelligence, a theoretical technology that matches the powers of the human brain.

In April, Ms. Simo took a leave of absence to deal with what was described as a chronic illness.

“It became clear that the road to recovery would be much longer and more complex than I had anticipated — and that I needed to focus on it fully,” she said in her post.

Ms. Simo, 40, did not immediately respond to a request for comment.

Her departure adds to the number of OpenAI executives who have changed roles or left the company in recent months. The company filed confidentially this year for an initial public offering, but has indicated that it may not be ready to go public for months.

Brad Lightcap left his longtime post as chief operating officer this year to move into a new role focused on “special projects.” Kate Rouch said she was stepping down as chief marketing officer in April to focus on cancer recovery. Kevin Weil, who oversaw science research after a brief stint as chief product officer, left OpenAI the same month.

(The New York Times sued OpenAI and Microsoft in 2023, claiming copyright infringement of news content related to A.I. systems. The two companies have denied those claims.)