Madrid: Ukraine's President Volodymyr Zelenskyy chided NATO for not embracing his embattled country more fully and asked for more weapons to fight Russia's invasion, as the leaders of the alliance met amid what its chief called its biggest crisis since World War II.
Russia's invasion of its neighbour shattered Europe's peace, drove NATO to pour troops and weapons into eastern Europe on a scale not seen since the Cold War and is set to give the defence organisation two new members in Sweden and Finland.
Members of the alliance have also sent billions in military and civilian aid to Ukraine. But Zelenskyy lamented that NATO's open-door policy to new members did not apply to Ukraine.
"The open-door policy of NATO shouldn't resemble old turnstiles on Kyiv's subway, which stay open but close when you approach them until you pay," Zelenskyy said by video link. "Hasn't Ukraine paid enough?" He asked for more modern artillery systems and other weapons and warned the leaders that they either had to provide Ukraine with the help it needed to defeat Russia or "face a delayed war between Russia and yourself".
Zelenskyy has acknowledged that NATO membership is a distant prospect. The alliance is trying to strike a delicate balance, letting its member-nations arm Ukraine without sparking a direct confrontation between NATO and nuclear-armed Russia.
As 30 NATO leaders met in Madrid, Secretary-General Jens Stoltenberg acknowledged the alliance is "in the midst of the most serious security crisis we have faced since the Second World War".
US President Joe Biden, whose country provides the bulk of NATO's military power, said the summit would send "an unmistakable message ... that NATO is strong and united".
"We're stepping up. We're proving that NATO is more needed now than it ever has been," said Biden.
He announced a hefty boost in America's military presence in Europe, including a permanent US base in Poland, two more Navy destroyers based in Rota, Spain, and two more F35 squadrons to the UK.
But strains among NATO allies have also emerged as the cost of energy and other essential goods has skyrocketed, partly because of the the war and tough Western sanctions on Russia.
There also are tensions over how the war will end and what, if any, concessions Ukraine should make to stop the fighting.
Money could also be a sensitive issue - just nine of NATO's 30 members currently meet the organisation's target of spending two per cent of gross domestic product on defence.
British Prime Minister Boris Johnson, whose country does hit the target, urged NATO allies "to dig deep to restore deterrence and ensure defense in the decade ahead".
The war has already triggered a big increase in NATO's forces in eastern Europe, and allies are expected to agree at the summit to boost the strength of the alliance's rapid reaction force nearly eightfold, from 40,000 to 300,000 troops, by next year.
The troops will be based in their home nations, but dedicated to specific countries on NATO's eastern flank, where the alliance plans to build up stocks of equipment and ammunition.
Stoltenberg said NATO was undertaking "the biggest overhaul of our collective defense since the end of the Cold War".
The leaders are also set to publish NATO's new Strategic Concept, its once-a-decade set of priorities and goals.
The last such document, in 2010, called Russia a "strategic partner". Now, the alliance is set to declare Moscow its No. 1 threat. The document will also set out NATO's approach on issues from cybersecurity to climate change - and the growing economic and military reach of China.
For the first time, the leaders of Japan, Australia, South Korea and New Zealand are attending the summit as guests, a reflection of the growing importance of Asia and the Pacific region.
Stoltenberg said China was not NATO's adversary, but posed "challenges to our values, to our interest and to our security".
Biden was due to hold a rare meeting with Japanese Prime Minister Fumio Kishida and South Korean President Yoon Suk Yeol on the sidelines of the summit, focused on North Korea's nuclear programme.
The summit opened with one problem solved, after Turkey agreed on Tuesday to lift its opposition to Sweden and Finland joining NATO.
In response to the invasion, the two Nordic nations abandoned their long-held nonaligned status and applied to join NATO as protection against an increasingly aggressive and unpredictable Russia - which shares a long border with Finland.
NATO operates by consensus, and Turkish President Recep Tayyip Erdogan threatened to block the Nordic pair, insisting they change their stance on Kurdish rebel groups that Turkey considers terrorists.
After urgent top-level talks with leaders of the three countries, alliance Secretary Stoltenberg said the impasse had been cleared.
Turkey hailed Tuesday's agreement as a triumph, saying the Nordic nations had agreed to crack down on groups that Ankara deems national security threats, including the Kurdistan Workers' Party, which is also considered a terrorist group by the US and the EU, and its Syrian extension.
It said they also agreed "not to impose embargo restrictions in the field of defence industry" on Turkey and to take "concrete steps on the extradition of terrorist criminals".
Stoltenberg said leaders of the 30-nation alliance will issue a formal invitation on Wednesday to the two countries to join.
The decision has to be ratified by all individual nations, but he said he was "absolutely confident" Finland and Sweden would become members.
Stoltenberg said he expected the process to be finished "rather quickly", but did not set a time on it.