Russian President Vladimir Putin on Saturday presided over a huge military parade to commemorate the 70th anniversary of victory over Nazi Germany, brushing off a snub by Western leaders over Ukraine.

In what is seen as punishment for the Kremlin's meddling in Ukraine, Western countries led by Russia's World War II allies are boycotting the May 9 festivities, leaving Putin to mark the day in the company of the leaders of China, Cuba and other Moscow-friendly figures.

President Vladimir Putin on Friday congratulated "citizens" of Ukraine but snubbed its leaders on the 70th anniversary of Soviet victory over Nazi Germany in WWII amid a deep feud between Moscow and Kiev. 

Putin pointedly sidestepped addressing Ukraine's pro-Western authorities as he issued a congratulatory statement to the governments of other former Soviet republics that fought alongside Moscow in WWII. 

The United States believes a hard-won Ukraine ceasefire accord is "imperfect" but still much better than having nothing at all to help resolve the bloody conflict, a senior U.S. official said Friday.

U.S. ambassador to NATO Douglas Lute said the agreements also offered "a glimmer of diplomatic hope" on ending a war between Kiev and pro-Russian rebels in eastern Ukraine which has cost more than 6,000 lives.

Europe held somber ceremonies to mark 70 years since victory over Nazi Germany on Friday as leaders warned of modern day threats such as the war in Ukraine and Islamic extremism.

Celebrations of the WWII victory in Europe were muted a day before Moscow throws a massive military parade which is being snubbed by Western leaders due to tensions over the crisis in Ukraine.

Ukrainian President Petro Poroshenko on Thursday criticized what he termed a policy of appeasement towards Russia in the context of the separatist conflict in Ukraine's east.

"Crimes are committed today in the 21st century amid the aggression against my country Ukraine, despite the cruelest lessons of the past," Poroshenko said in the Polish port city of Gdansk.

European Commission head Jean-Claude Juncker called again Thursday for the bloc to build an army, saying a flock of hens posed more of a threat than its current military capabilities.

"A bunch of chickens looks like a combat formation compared to the foreign and security policy of the European Union," Juncker told a Brussels forum in typically lively language.

Pro-Russian separatists appear to be making preparations for a fresh offensive in eastern Ukraine, U.S. Defense Secretary Ashton Carter told lawmakers on Wednesday.

The Pentagon chief also said that sanctions imposed by European countries and a decline in oil prices were the most effective way to exert pressure on Russia over its role in the conflict.

Ukraine said Wednesday that five Ukrainian soldiers were killed as fresh clashes rumbled on despite the resumption of talks between the government and rebels over a battered truce deal.

Over the past 24 hours four servicemen died when their armored vehicle hit a landmine close to the frontline town of Avdiivka in the ravaged east, while a fifth was killed in an insurgent ambush and a further 12 wounded, Ukrainian spokesman Andriy Lysenko said.

Conflicts and violence in places like Syria and Ukraine have displaced a record 38 million people inside their own countries, equivalent to the total populations of New York, London and Beijing, a watchdog group said Wednesday.

Nearly one third of them -- a full 11 million people -- were displaced last year alone, with an average of 30,000 people fleeing their homes every day, the Geneva-based Internal Displacement Monitoring Centre (IDMC) said in a report.

A Ukrainian army volunteer was killed and three soldiers were wounded in fighting in the country's east, Kiev said Tuesday, while pro-Russian rebels said one of their fighters was injured.

A volunteer died from his wounds on Monday after being hit by 120mm mortars fired by rebels at Ukrainian fighters who are stationed near the ruined airport of rebel hub Donetsk, the chief of staff of the Ukrainian armed forces said.