* Putin commemorates Russia's landmark 1812 victory
* Urges unity as religious violence spreads beyond Caucasus
President Vladimir Putin made a rousing call for unity among Russia's diverse ethnic and religious groups on Sunday as he led commemorations of a battle 200 years ago that led to the defeat of Napoleon Bonaparte.
Standing by a monument at the scene of the 1812 Battle of Borodino, 120 km (75 miles) west of Moscow, Putin delivered a speech extolling the virtues of patriotism that enabled Russia to repel the French army in 1812.
Back as president since May, Putin faces more open opposition in big cities than at any time since he first rose to power in 2000, and a persistent Islamic insurgency in the North Caucasus.
For the second time in five days he called for unity, underlining his concern that the insurgency could spread and threaten the integrity of Russia, home to many nationalities and religions.
"Only when Russia's nations were united, were together, they achieved the best results in the development of their fatherland," Putin told Russian and foreign dignitaries, including former French president Valery Giscard d'Estaing.
"By and large patriotism, which was the basis of all our major victories, comes down to the unity of the Russian nation."
Putin also evoked the Battle of Borodino to rally Russians behind him in his successful presidential election bid last winter.
The Islamic insurgency in the North Caucasus, more than a decade after Putin toppled a separatist government in Chechnya, could also undermine unity in other parts of Russia.
The killing of a Muslim cleric in July in the central province of Tatarstan, in Russia's heartland, showed violence may be spreading to other mainly Muslim regions.
The Battle of Borodino on Sept. 7, 1812, remembered by Russians as an epic victory, is commemorated in Lev Tolstoy's novel "War and Peace".
Neither side won a decisive victory in the battle and tens of thousands of soldiers were killed on both sides before the Russians withdrew and abandoned Moscow to the French.
The Russian troops regrouped and the French, after occupying Moscow, were forced by badly stretched supply lines, the cold winter and lack of reinforcements, to withdraw from Russia, constantly harassed by Russian forces.
Putin, speaking after laying a wreath at the monument close to the field where actors re-enacted the battle, also used the anniversary to call for unity between European nations.
"Such occasions as today do not only serve to remember bloody events. This is a good reason to speak about how we should build relations with our neighbours, our current friends in the common European home," he said.
"I'm deeply convinced that real reconciliation and respect for the past, for our common history, for the heroism of our predecessors, for the honour and bravery of the soldiers carrying out their war duty, is the foundation for really friendly relations between countries and nations," he said.
Russians also take pride in their country's effort to defeat Nazi Germany in World War Two, which began on Sept. 1, 1939, at the cost of millions of Soviet soldiers and civilians.
"We were more often together than at war. France was always our strategic ally," Putin told Giscard d'Estaing. "I hope we will manage with our friends from France and other European countries to do more to unite Europe on the basis of moral values."
Tens of thousands of Russians and foreigners gathered at the scene of the battle on Sunday to watch the colourful re-enactment by more than 3,000 military enthusiasts.
Nine planes were used to disperse clouds over the scene, but rain soon covered the field, along with grey smoke steaming from historic weaponry.
"The level of patriotism in our country has sunk in the last 25 years. Such events help to bring it back," said Alexei Rogatnev from St Petersburg, dressed as a 19th century Russian soldier.