Ukrainian President Petro Poroshenko on Monday accused Russia of sending major military backup to pro-Moscow rebels, speaking just ahead of talks on the conflict with German Chancellor Angela Merkel and French President Francois Hollande.

"Just this week three big convoys crossed our border towards Lugansk, Donetsk and Debaltseve," Poroshenko said, referring to rebel-controlled areas of eastern Ukraine.

Poroshenko was set to meet Hollande and Merkel in Berlin later Monday for talks to discuss the recent resurgence of violence in Ukraine.

Merkel and Hollande have put enormous political onus on resolving Ukraine's 16-month pro-Russian uprising and returning peace to the European Union's turbulent eastern front.

Monday's talks will be notable for their diplomatically-charged exclusion of Russian leader Vladimir Putin.

In a speech in Kiev for Independence Day celebrations, Poroshenko accused Russia of having sent a total of up to 500 tanks, 400 artillery systems and up to 950 military armoured vehicles to pro-Russian rebels, apparently talking about the whole conflict, although he did not specify the time period for these deliveries.

Kiev and Western countries accuse Russia of supplying arms to the rebels and deploying regular troops in the separatist east, which Moscow denies.

Merkel and Hollande met Putin and Poroshenko in the Belarusian capital Minsk in February, emerging with a peace deal that promised to end the fighting quickly and resolve all political disputes by the end of the year.

The peace deal has since repeatedly been broken by both sides. The death toll in the 16-month-long war is now close to 6,900.

Poroshenko said that 50,000 Russian soldiers are deployed on the border with Ukraine and 9,000 Russian servicemen are among the 40,000 fighters of the separatist force.
Despite Western sanctions that "deal Russia's economy a hard blow," Moscow "has still not given up the idea of a direct intervention or a rebel assault in the country's interior," Poroshenko said.

"The war for independence is still continuing and we can only claim victory by combining our defensive efforts, diplomatic talent, political responsibility and steely endurance," Poroshenko said.

He was speaking at a military parade in Kiev to celebrate 24 years since Ukraine gained independence from the Soviet Union.
"We must spend our 25th year of independence as if we are skating on fragile ice. The smallest careless step could be fatal," Poroshenko said.

The parade along Kiev's main street did not include heavy military hardware like last year.

Soldiers who had fought in the east marched through Kiev, cheered by Ukrainians, most of them wearing their national dress of embroidered shirts.

In Donetsk, the rebels' de facto capital, some 300 people gathered in the city centre to condemn what they called "Dependence Day", carrying placards saying "No to Fascism!", "Poroshenko, you have blood on your hands" and "We are against the war," an AFP journalist saw.