WARSAW, Poland — President Andrzej Duda marked Poland’s Independence Day on Monday with a call for sustained U.S. commitment to Europe’s security in view of Russian aggression in the region and argued that Ukraine’s pre-2014 borders should be restored.

Duda spoke as the nation marked the 106th anniversary of its restored independence at the end of World War I after more than a century of being partitioned and ruled by Russia, Germany and Austro-Hungary.

Across Poland, people gathered to celebrate a day that carries weight for a nation where the bitterness of losing national sovereignty remains a powerful force in political life. For some, it means seeking a strong nation-state that does not relinquish sovereignty to the European Union or other international bodies.

In Warsaw, tens of thousands of people took part in a march organized by nationalist groups, which has sometimes seen violent clashes in past years. Organizers estimated the turnout at around 100,000.

Police said they detained 75 people and seized banned items from participants, including pyrotechnic materials, knives, telescopic batons and brass knuckles.

Weighing on the minds of many is the war across Poland’s border in Ukraine, and an expectation that President-elect Donald Trump’s return to the White House will bring a change to the security situation in the region whose effects will be felt for many years.

Some fear Trump could end the U.S. commitment to NATO, or make a deal with Russian President Vladimir Putin that could result in a permanent loss of territory for Ukraine and encourage Russia to attack other nations. Others believe Trump could be the Western leader with the leverage to persuade Putin to stop the fighting.

Duda, who has had friendly relations with Trump, said in a speech in Warsaw that Europe will continue to need U.S. protection.

“It is a pipe dream – as some people think – that Europe can ensure its own security today,” Duda said.

He emphasized that the security guarantees of successive U.S. presidents are extremely important in times of resurgent Russian imperialism.

“Today we have no doubts that for the security of Europe and the world, it is necessary to strengthen Euro-Atlantic ties,” Duda said.

“Today we have no doubts that if we are strong and responsible, peace will last in our part of Europe, we will survive all the turmoil of history and an independent, sovereign Republic of Poland will also last.”

He said the territorial integrity of all countries, especially Ukraine, should be respected and it “must return to its borders from before the Russian attack, not only the one in 2022 but also the first one, in 2014.”

Russia annexed Ukraine’s Crimean Peninsula in 2014 and launched its full-scale invasion in 2022.