NATO demanded yesterday (4 September) that Moscow withdraw its troops from Ukraine, as US President Barack Obama and his Western allies vowed to support Kyiv and buttress their own defences against Russia in the biggest strategic shift since the Cold War.

NATO leaders made clear at a summit in Wales that their military alliance would not use force to defend Ukraine, which is not a member, but planned tougher economic sanctions to try to change Russian behaviour in the former Soviet republic.

The two-day meeting, hosted by UK Prime Minister David Cameron, was marked by the most serious east-west standoff since the fall of the Berlin Wall 25 years ago and the collapse of the Soviet bloc, as well as alarm at territorial gains by Islamist insurgents in Iraq and Syria.

Western officials voiced deep caution about Kremlin talk of an imminent ceasefire in a five-month-old armed revolt by pro-Russian separatists in eastern Ukraine, timed just as NATO was meeting and the European Union was preparing new sanctions.

Previous such statements had proved to be "smokescreens for continued destabilisation of Ukraine", NATO Secretary-General Anders Fogh Rasmussen told reporters after the 28 leaders met Ukrainian President Petro Poroshenko.

"We call on Russia to end its illegal and self-declared annexation of Crimea," Rasmussen declared. "We call on Russia to pull back its troops from Ukraine and stop the flow of arms, fighters and funds to the separatists. We call on Russia to step back from confrontation and take the path of peace."

Rasmussen said the alliance would provide strong support to help Ukraine improve its own security. “Our support is concrete and tangible,” he said.

The Ukrainian press quoted Poroshenko as saying that Ukraine has been promised by NATO countries the delivery of non-lethal, but also lethal weapons, including “high-precision weapons”.

He also said that the issue of Ukraine’s membership to NATO will be raised once the country makes the necessary reforms.

“When the country will answer to all requirements for membership, the citizens will decide how and when the accession of Ukraine to NATO could take place”, the Ukrainian Pravda quoted Poroshenko.

Ceasefire, peace plan

Poroshenko, whose forces have suffered a string of setbacks in the last week, told reporters he would order a ceasefire today if an agreement on a peace plan to end the war in eastern Ukraine is signed at talks in the Belarus capital of Minsk.

"The only thing we need now for peace and stability is just two main things: first, that Russia withdraw their troops, and second, to close the border," the Ukrainian leader said, adding he was cautiously optimistic about today's peace talks.

"At 1400 local time (1100 GMT today), provided the [Minsk] meeting takes place, I will call on the General Staff to set up a bilateral ceasefire and we hope that the implementation of the peace plan will begin tomorrow," Poroshenko told reporters.

Meanwhile, Alexander Zakharchenko, head of the main rebel Donetsk People's Republic, said in a statement his men would also order a ceasefire, starting one hour later, provided that Kyiv's representatives signed up to the peace plan at the Minsk meeting.

A NATO military officer said Moscow had "several thousand" combat troops and hundreds of tanks and armoured vehicles operating in Ukraine. The Kremlin denies it has any forces fighting alongside the rebels.

Sanctions cooking

The White House said Obama and leaders of Germany, France, Britain and Italy agreed on the sidelines of the summit that Russia should face "increased costs" for its actions.

A White House official attending the NATO summit said the United States was preparing a new round of economic sanctions, but progress towards a truce could halt new European financial sanctions that EU leaders had been expected to agree today. 

French President François Hollande said those new sanctions would depend on events in the coming hours. Diplomats said there was little chance of them being derailed, even if a ceasefire were signed.

German Chancellor Angela Merkel, however, warned that while NATO members wanted a political solution and would talk to Russia about this, "We're also prepared to lend weight to our political demands by imposing further sanctions."

France, which has faced fierce pressure from Washington and other NATO allies to halt the sale of two helicopter carriers to Russia, said on 3 September it would not for now deliver the first of the warships due to Moscow's actions in Ukraine. Hollande said the deal was not cancelled or suspended, but a ceasefire and a political settlement were necessary for delivery.

>> Read: France suspends Mistral delivery to Russia

Russia warns

Poroshenko avoided public talk of reviving Ukraine's bid to join NATO, which had reopened a rift among the allies. Obama said in Estonia on Wednesday that the door to membership would remain open to states that meet NATO standards and "can make meaningful contributions to allied security", but France and Germany remain opposed to admitting Kyiv, fearing it would exacerbate tension with Moscow and could suck them into a war.

Russian Foreign Minister Sergei Lavrov underlined Moscow's opposition to Ukraine joining NATO, warning that attempts to end the country's non-aligned status could harm security. He accused the United States of supporting "the party of war" in Kyiv.

After a week of defiant statements from Putin, Lavrov said Russia was ready for practical steps to de-escalate the crisis and urged Kyiv and the rebels to heed ceasefire proposals put forward by Moscow on 3 September.

As the NATO summit was ongoing, Poroshenko's forces were battling to cling to the key port of Mariupol on the Sea of Azov, which is vital to Ukrainian steel exports. Explosions were heard close to the city, halfway between Crimea and Russia.

New NATO bases?

Eastern European NATO members, including Poland, wanted NATO to station thousands of troops permanently on their territory to deter any possible Russian attack.

But NATO members have spurned that idea, partly because of the expense and partly because they do not want to break a 1997 agreement with Russia under which NATO committed not to base significant combat forces in the east.

Instead, leaders will agree to pre-position equipment, fuel and ammunition in eastern European countries with bases ready to receive the NATO rapid reaction force if needed.

The Baltic states Latvia, Lithuania and Estonia, the only parts of the former Soviet Union to be admitted to NATO, fear Moscow could meddle in their affairs with the same rationale it applied in Ukraine - protecting Russians. All three have significant Russian minorities.

So far, Western military support for Ukraine has been mostly symbolic. NATO leaders approved a package of support for Kyiv, pledging trust funds worth some €15 million to improve Ukrainian military capabilities in logistics, command and control and cyber defence.

A dozen countries will join an exercise in Lviv, Ukraine, later this month, co-hosted by Ukraine and the US Army.