Former Polish prime minister Donald Tusk took over as president of the European Council of EU leaders on Monday, promising strong leadership in foreign policy and "ruthless determination" to end Europe's economic crisis.
The center-right Tusk, 57, who led Poland for seven years of economic growth and rising EU influence, succeeded Herman Van Rompuy, 67, a self-effacing Belgian who forged crucial compromises to save the eurozone as the first holder of the job created in 2009.
"We have also enemies, not only sceptics. Politics has returned to Europe. History is back. In such times we need leadership and political unity," Tusk said, referring obliquely to severe tension with Russia over Ukraine.
"Europe has to secure its borders and support those in the neighborhood who share our values," he said in English at a brief handover ceremony during which he admitted being "a little nervous".
He also said the coming year would be crucial for relations between Europe and the United States, with the world's two biggest trading blocs negotiating a free trade agreement that faces opposition on both sides of the Atlantic.
Tusk said later he had discussed the trade agreement and the Ukraine crisis in a phone call with U.S. President Barack Obama.
"We agreed to step up our efforts towards reaching agreement," he said in a statement, referring to the trade pact.
On Ukraine, Tusk said: "We ... agreed on how important it is for Russia to withdraw from eastern Ukraine, to stop supplying troops and equipment, to allow effective control of the border and to allow the OSCE to carry out its mission."
Tusk faces his first challenge on Dec. 18-19 when the 28 EU leaders will seek an agreement on a European investment fund designed to revive jobs and growth by drawing private capital into transport, energy and digital network projects, and debate economic reforms and national budget discipline.
The German-speaking Pole was keen to demonstrate he has made progress in English and French, the main working languages of the EU, with a line of French to end his remarks.
EU officials expect Tusk to be more assertive in foreign policy, notably towards Russia, than was Van Rompuy, whose main focus was financial crisis management. His chief foreign affairs dviser will be U.S.-born Estonian diplomat Riina Kionka, who worked in the 1980s at U.S.-owned Radio Free Europe, which broadcast news and opinion into then communist Eastern Europe.
However, the powers of the president of the European Council are circumscribed by the Lisbon Treaty, which defines the job as chairing and preparing EU summits and representing the bloc at head of state level with third countries.