MOSCOW (Reuters) - President Dmitry Medvedev struck a conciliatory note at Russia’s Victory Day military parade on Sunday, urging world powers to unite for peace and defending his decision to invite NATO troops to march on Red Square.

For the first time since Stalin began commemorating the Soviet Union’s victory over Nazi Germany, serving U.S., British Polish and French troops joined over 11,000 Russian soldiers to parade past the Kremlin’s red walls in bright sunshine.

The opposition Communists and some Soviet war veterans condemned the move but Medvedev said in a speech that the lesson from World War Two was “to urge us to unite in solidarity” to counter present-day threats and ensure global security.

“Today, at the military parade, soldiers of Russia, of countries of the (former Soviet Union), and of the Allied powers will march together, in one column which is evidence of our common readiness to defend peace,” he said.

Welsh Guards from the British military marched in their trademark black bearskin hats ahead of 70 troops from the U.S. 170th Infantry Brigade in a section reserved for the Soviet Union’s war allies.

Underlining the message of reconciliation, a 1,200-strong military band closed the parade with a moving rendition of Beethoven’s Ode to Joy as German Chancellor Angela Merkel, Chinese President Hu Jintao and other world leaders looked on.

Russia’s Communists, still the country’s biggest opposition party, held a demonstration after the parade, chanting “Glory to the great Stalin,” to protest against NATO forces for marching over the square, home to the embalmed body of Lenin.

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Most of the Soviet war veterans attending the parade seemed unconcerned by the presence of NATO soldiers, though they did not applaud when they marched past.

“Why not? Let them see how we celebrate a solemn parade,” said ex-World War Two soldier Grigory Petrovich Zabuski. “I’m absolutely not against it. I met English troops myself on the Elbe on May 4, 1945.”

But not everyone was happy.

“We veterans were against this from the beginning,” said one former naval officer, who declined to give his name. “The Americans have their interests everywhere, even in our country. Remember when (then U.S. Secretary of State) Madeleine Albright said it was not fair that all of Siberia belonged to Russia ?”

President Barack Obama, unable to come to Moscow because of a scheduling clash, praised the historic invitation to NATO troops, saying Medvedev had shown “remarkable leadership in honoring the sacrifices of those who came before us.”

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BIGGEST EVER

A poll by the independent Levada Center last month showed that 55 percent of Russians were wholly or partly positive about NATO troops at the parade, with only 28 percent against.

The result may reflect better ties between Moscow and Washington since Obama’s election and his “reset” of relations.

Victory Day is one of Russia’s most important public holidays and Defense Minister Anatoly Serdyukov said this year’s commemorations would be among the biggest, with over 102,000 troops marching in cities across this vast country.

French President Nicolas Sarkozy and Italian Prime Minister Silvio Berlusconi canceled their attendance at the last minute to deal with the crisis surrounding the euro currency.

Russian leader Vladimir Putin revived two years ago a Soviet-era tradition of parading tanks, missiles and military vehicles across the square and flying aircraft overhead.

This year’s parade included 127 helicopters, fighters, bombers, reconnaissance aircraft and refueling planes which screamed over Red Square at low altitudes in close formation.

Behind the ceremony and the celebrations, serious business was transacted. Putin, who is now Prime Minister, hosted a meeting and dinner at his country retreat for China’s Hu.

Putin’s spokesman Dmitry Peskov said afterwards only that discussions were substantive.