European leaders have named the Polish prime minister, Donald Tusk, as the next EU president and Italian foreign minister Federica Mogherini to head its diplomatic service, as the bloc faces a series of challenges topped by Ukraine.
Tusk, who speaks only halting English and no French, is the first eastern European to hold such a senior post in the EU and is known as a tough critic of the Kremlin, especially over the Ukraine crisis.
The appointments were announced on Saturday after a meeting of EU leaders in Brussels.
I come to Brussels from a country that deeply believes in the significance of Europe.
The current EU president, Herman Van Rompuy, said the new team faced three major challenges: the stagnating European economy, the crisis in Ukraine which he called "the gravest threat to continental security since the Cold War", and Britain's place in the EU.
"I come to Brussels from a country that deeply believes in the significance of Europe," the centre-right Tusk told a news conference with Van Rompuy and Mogherini.
He insisted that "no reasonable person can imagine the EU without the UK" and pledged to do everything possible to meet London's demands for reform.
The UK's prime minister, David Cameron, said he was "delighted" by Tusk's appointment and by his comments.
Tusk will take office on December 1 while Mogherini, if confirmed by the European Parliament, will start her new job on November 1.
Tusk is a pro-European free marketeer with roots in Poland's Solidarity anti-Soviet trade union who has been prime minister since 2007.
The German chancellor Angela Merkel said Tusk "faced big challenges" and lauded him as "a qualified, committed and passionate European, 25 years after the fall of the Berlin Wall, 25 years after the end of the Cold War."
Tusk denied his poor command of foreign languages would handicap him as EU president, a job that requires a deft touch to find compromise amid conflicting positions and prepare European leaders for often delicate summits.
With leaders unnerved by Russia's latest actions in Ukraine, the nomination of Tusk to replace Belgium's Van Rompuy could send a message of resolve to Moscow as EU leaders also consider fresh sanctions.