This Nato summit marks the organisation’s 75th anniversary.

Founded in 1949 four years after the end of World War Two for the collective defence of its members, it linked the security of the US with its European allies against the Soviet Union.

By 1949, Soviet dictator Stalin had managed to install communist governments in most Eastern European countries to act as a "buffer zone" to protect the Soviet Union from attack. There was a fear that the Soviet Union could do the same to countries in Western Europe.

The Berlin Blockade of 1948 convinced the West that they needed a defensive organisation, in the event of a Soviet attack on a capitalist country.

The US was concerned that communism would now spread to other countries and the formation of Nato meant that the US could place weapons in member states.

The organisation witnessed the end of communism - defeating the Soviet bloc without firing a shot. It went to war for the first time in the Balkans in the 1990s.

It then set out on a new path - so-called "out of area" operations beyond Nato's frontiers, notably its operations in Afghanistan and the wider war against terror.

Image source, Getty Images

US President Joe Biden said at the summit yesterday that Nato was "as united as it has ever been" and later today, he will reaffirm his country’s "unwavering commitment to the transatlantic bond and Article 5 of the Washington Treaty – that an attack on one is an attack on all", according to a White House statement.

The statement further lays out that the leaders gathered in Washington would advance the implementation of Nato’s new defence plans, "ensuring Allies are prepared to deter threats and defend every inch of Nato territory".

Ahead of today's gathering, it also released a statement setting out what it will achieve:

• A stronger, reinvigorated and more robust alliance
• Support for Ukraine
• Increased defence spending and strengthened defence industrial base
• Modernised deterrence and defence
• Strengthening global partnerships
• Strengthened resilience
• Cyber defence
• Advancing the women, peace and security agenda across Nato's Core Tasks
• Combatting terrorism and addressing challenges beyond Nato's southern flank

Nadine Yousif
BBC News, Toronto

Image source, Getty Images

Canada is under mounting pressure to increase its military spending as it continues to fall short of the target set out for Nato members, raising fears that the country is becoming an outlier among its allies.

That message is expected to be made clear as Prime Minister Justin Trudeau attends the Nato summit in Washington to mark the military alliance’s 75th anniversary.

Canada, one of Nato's founding members, ranks seventh overall in the amount of money spent on defence among the 32-nation alliance.

But it falls way short of the alliance’s doctrine, which requires Nato countries to spend at least 2% of their GDP on the military.

Using that metric, Canada - which spends 1.34% of GDP - is ahead of only Slovenia, Turkey, Spain, Belgium and Luxembourg in the alliance.

By contrast, the UK spends just over 2% of its GDP on its military, while the US spends nearly 3.5%.

Read more from Nadine here

Nato requires member states to spend at least 2% of their GDP on defence.

The US spends nearly 3.5%, and several countries which border Russia - such as Poland, Estonia, Latvia and Lithuania - also spend more than 2% on their armed forces. The UK spending is currently just above 2%.

A number of countries, including France, Germany, Italy and Spain spent less than the 2% target in 2023.

Former US President Donald Trump, who is campaigning for re-election, controversially said he would encourage Russia to attack Nato countries which failed to spend enough on defence.

Nato said there was an "unprecedented rise" in defence spending by several members in 2023, and that 18 countries were expected to meet the 2% level in 2024.

Read BBC Verify’s dive into Nato members’ defence spending

US President Joe Biden pledged to provide Ukraine with five new strategic air defence systems to counter relentless Russian attacks.

In a forceful speech welcoming Nato leaders to Washington DC on Tuesday, the president declared the military alliance "more powerful than ever" as it faced a "pivotal moment" in the war between Russia and Ukraine.

Biden said the US would partner with Germany, Italy, the Netherlands and Romania to donate Patriot missile batteries and other advanced systems to aid Ukraine, as Russia continues to launch air attacks including one on Monday which hit a children's hospital in Kyiv.

The city's mayor, Vitali Klitschko, said Monday's bombardment was among the worst since the beginning of Russia's full-scale invasion in February 2022.

The North Atlantic Treaty Organization (Nato) was formed in 1949 by 12 countries, including the US, UK, Canada and France.

Its aim was to block expansion by the Soviet Union - a group of communist states including Russia.

The alliance's key role is mutual defence of its member states. So if one is attacked, then all the Nato countries agree to come to its defence.

Nato does not have an army of its own, but member countries can take collective military action in response to crises. They also co-ordinate military plans and carry out joint military exercises.

Nato said Russia's full-scale invasion of Ukraine in 2022 posed the "most significant and direct threat to allies' security".

Image source, EPA

Nato has 32 members across Europe and North America, including the UK, US, Canada, France, Germany, Italy, Spain and Turkey.

After the Soviet Union's collapse in 1991, many Eastern European countries joined: Albania, Bulgaria, Hungary, Poland, the Czech Republic, Slovakia, Romania, Lithuania, Latvia and Estonia.

Sweden and Finland applied to join in May 2022, following Russia's invasion of Ukraine. They had been neutral for decades.

Finland - which has a 1,340km (832 mile) land border with Russia - joined in April 2023. Sweden became a member in March 2024.

The addition of Sweden and Finland represents the biggest Nato expansion since the 1990s. The two countries contribute nearly 300,000 active and reserve troops to the alliance's ranks.

Ukraine, Bosnia and Herzegovina, and Georgia also hope to join Nato.

Image source, Reuters

Good afternoon and welcome to our coverage of day two of the 2024 North Atlantic Treaty Organisation (Nato) summit taking place in Washington DC.

The summit commemorates the 75th anniversary of Nato, with the key topics set to include assistance for Ukraine, deterrence and defence and stepping up partnerships.

Yesterday, we heard from US President Joe Biden who pledged to provide Ukraine with five new strategic air defence systems.

Today we're expecting to hear more from Nato heads of state and government as well as well as the alliance's outgoing secretary general Jens Stoltenberg.

Stay with us as we bring you the latest news and analysis out of DC.