Ukrainian Prime Minister Arseny Yatseniuk has accused Russian President Vladimir Putin of trying to destroy Ukraine as an independent country and said only Nato could defend the ex-Soviet republic from external aggression.

Kiev and its western backers accuse Moscow of sending troops and tanks into eastern Ukraine in support of pro-Russian separatists battling Ukrainian forces in a conflict that has killed more than 3,000 people.

"Let me put it bluntly, we are still in the state of war, and the key aggressor is the Russian Federation. And until we get the peace it would be really difficult to have real changes," Yatseniuk told a conference attended by European and Ukrainian politicians and business leaders on Saturday.

[Vladimir Putin's] goal is to take the entire Ukraine. He cannot cope with an idea that Ukraine would be a part of big EU family. He wants to restore the Soviet Union.

- Arseny Yatseniuk, Ukrainian prime minister

Talking about Vladimir Putin, Yatseniuk said that "his goal is to take the entire Ukraine. He cannot cope with an idea that Ukraine would be a part of big EU family. He wants to restore the Soviet Union."

Yatseniuk said Putin would not be content only with Crimea - annexed by Moscow in March - and with Ukraine's mainly Russian-speaking eastern region.

"Russia is a threat to the global order and to the security and stability in the entire Europe. At the first stage he decided to annex Crimea, at the second one he want to build up a frozen conflict in Donetsk and Luhansk, at the third one he wants to facilitate the corridor from Donetsk and Luhansk to Kherson, Odessa and Transnistria, and at the fourth one he wants to eliminate Ukraine as an independent country, this is my take on this," the Ukrainian prime minister said.

Attack on airport

A fragile ceasefire negotiated by envoys from Ukraine, Russia, the separatists and Europe's OSCE security watchdog, has been in place in eastern Ukraine for more than a week and is broadly holding despite sporadic violations.

Renewed fighting flared up on Saturday in Donetsk between pro-Russian rebels and government forces, while Moscow sent a second convoy of trucks into Ukraine without Kiev's consent.

Ukraine's military said in a statement that it had successfully repelled a rebel attack on the government-held Donetsk airport, which came under artillery fire from rebel positions late on Friday.

Continuous rocket fire could be heard overnight. A statement posted on the city council website said that shells had hit residential buildings near the airport, although no casualties were reported.

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A column of three GRAD rocket launchers - all its rockets still in place - was seen moving freely through the rebel-held city on Saturday morning.

"We had what appeared to be rocket fire or mortar rounds landing in the vicinity of the airport, which is still under the control of Ukrainian forces," said Al Jazeera's Robin Forestier-Walker, reporting from Donetsk. The airport, he said, is "a very important strategic position which the rebels here would very much like to take control of".

Nato protection

Meanwhile, asked about future Nato membership, a red line for Russia, Yatseniuk said he realised the alliance was not ready now to admit Kiev, but still advocated for Nato membership for Ukraine saying that was the only defence Kiev might have.

"So the idea is to say it bluntly and clearly that Nato in these particular circumstances is the only vehicle how to protect and defend Ukraine. I do understand that not all Nato members were happy with this kind of statement. But my job is to make happy the people of Ukraine," Yatseniuk said.

There is no prospect of the Atlantic alliance admitting Ukraine, a sprawling country of 45 million people between central Europe and Russia, but Kiev has stepped up cooperation with Nato in a range of areas and has pressed member states to sell it weapons to help defeat the separatists.

"I do understand that in a short-term perspective Nato is not ready to accept Ukraine. But you know, ask and you will be given. Well, it's about Bible. And knock, and the door will be opened. So we decided to knock," Yatseniuk said.

Source: Al Jazeera and agencies