UNITED NATIONS—Security Council diplomats grappling with questions about Europe’s peace and security were divided Tuesday on a key issue: the role of Russia.

Western diplomats called Russia the biggest destabilizing force in Europe because of its incursion into Ukraine while some Central European countries contended the only solution for Europe’s concerns involved closer ties between U.S. and Russia. U.S. Ambassador Nikki Haley took a middle road, reassuring Council members that the Trump administration remains committed to the North Atlantic Treaty Organization.

Ms. Haley said the U.S. wants better relations with Russia but that it wouldn’t compromise on its position of support for Ukraine’s sovereignty. She added that the U.S. wouldn’t back away from supporting its longtime ally, the European Union, despite occasional policy differences.

“The United States thinks it’s possible to have a better relationship with Russia,” said Ms. Haley. “But greater cooperation with Russia cannot come at the expense of the security of our European friends and allies.”

Ms. Haley’s comments follow a pattern set by other administration officials, including Vice President Mike Pence and Defense Secretary Jim Mattis, who recently have sought to assure allies in Europe and Iraq concerned about comments by President Donald Trump, who has suggested NATO was obsolete and that the U.S. should take control of Iraq’s oil production.

The topic of closer ties between Russia and U.S. and a potential shift toward Russia by the Trump administration has preoccupied diplomats and U.N. officials. But not all are against such a shift.

Hungary’s foreign minister, Péter Szijjártó, who attended the Council meeting on Tuesday, said in an interview that his country fully supports closer Russia and U.S. diplomatic relations because the challenges faced by Europe are too robust for a divided European Union to conquer on its own. Hungary is a NATO member, but has drifted more closely to Russia in recent years.

“Without U.S. and Russia it wouldn’t be possible to find solutions for the problems in central Europe,” said Mr. Szijjarto, who is optimistic that Hungary will have better ties with the Trump administration because the conservative political party in power there shares many of Mr. Trump’s views on migration and policies based on self-interest.

Still, others voiced different views. U.K. Ambassador Matthew Rycroft called Russia a “destabilizing” force in Europe that was supporting a terrorist insurgency in Eastern Ukraine and “seeking to destabilize and undermine NATO.”

The Security Council debate came a day after Russia’s Ambassador to the U.N., Vitaly Churkin, 64 years old, died unexpectedly. The Council opened with a minute of silence for Mr. Churkin, and commemorative comments by all diplomats on the 15-member Council, expect for Ukraine.

Europe’s security challenges aren’t limited to Russia. The continent faces an upsurge in migration, with refugees arriving from conflict zones in Africa and the Middle East, and has been at the forefront of attacks by Islamic State terrorist group.

Britain’s exit from the European Union, which will go into motion in March, has led the way for nationalist conservative, anti-globalization and anti-immigration political parties to gain momentum.

The U.N.’s secretary-general, Antonio Guterres, addressed the Council on Tuesday saying that no single factor can be blamed for the security situation and conflicts emerging in Europe.

“Populism, nationalism, xenophobia and violent extremism are causes and effects of conflict in Europe,” Mr. Guterres tweeted afterward.