Justin Trudeau has volunteered Canada’s military to lead the first year of a Nato training mission in Iraq, as Donald Trump berated alliance members for not spending enough on defence.

At a highly anticipated Nato meeting in Brussels on Wednesday, the Canadian prime minister pledged to provide helicopters and 250 troops, saying it was important to build-up the war-ravaged country's defences against Isis.

Persuading Nato allies to spend more on defence is one of Mr Trump’s key foreign policy proposals and Canada’s new offering may abate his complaints about the nation not meeting the benchmark.

Mr Trudeau said Canada had "no plans" to meet demands that it comply with Nato’s benchmark for defence spending.

Canada only spends 1.23 per cent of gross domestic product (GDP) on defence – according to the military alliance’s figures published on Tuesday – and plans to raise this to 1.4 per cent by 2024.​

Nato asks its members to set aside the equivalent of two per cent of their GDP, but only a handful of the 29 alliance members currently meet the target.

Mr Trump launched a stinging attack on his Nato allies as he made his way to the gathering, saying in a Twitter post: "Many countries in Nato, which we are expected to defend, are not only short of their current commitment of 2 per cent (which is low), but are also delinquent for many years in payments that have not been made. Will they reimburse the U.S.?

He later added: "The European Union makes it impossible for our farmers and workers and companies to do business in Europe (US has a $151bn trade deficit), and then they want us to happily defend them through Nato, and nicely pay for it. Just doesn’t work!"

Last month, the US and its longtime allies Europe and Canada stood on the brink of a trade war after Mr Trump threatened to impose harsh duties on steel and aluminium.

Nato leaders gather for summit: in pictures Show all 10 1 /10 Nato leaders gather for summit: in pictures Nato leaders gather for summit: in pictures World leaders gather for Nato family photo Getty Images Nato leaders gather for summit: in pictures British Prime Minister Theresa May arrives EPA Nato leaders gather for summit: in pictures President Donald Trump talks to British Prime Minister Theresa May EPA Nato leaders gather for summit: in pictures U.S. President Donald Trump, left, talks to British Prime Minister Theresa May during a family photo at a summit of heads of state and government at NATO headquarters in Brussels Wednesday, July 11, 2018. NATO leaders gather in Brussels for a two-day summit to discuss Russia, Iraq and their mission in Afghanistan. (AP Photo/Markus Schreiber) Markus Schreiber AP Nato leaders gather for summit: in pictures US President Donald Trump and Nato Secretary General Jens Stoltenberg attend a bilateral breakfast ahead of the Nato Summit in Brussels Reuters Nato leaders gather for summit: in pictures President Donald Trump, right, gestures as he speaks to the media prior to his bilateral breakfast with Nato Secretary General Jens Stoltenberg, left AP Nato leaders gather for summit: in pictures President Donald Trump, US Secretary of Defence James Mattis and US Secretary of State Mike Pompeo at the bilateral breakfast with Nato Secretary General Jens Stoltenberg REUTERS Nato leaders gather for summit: in pictures President Donald Trump and Mike Pompeo, left, are reflected in a mirror as they attend at a breakfast meeting AFP/Getty Images Nato leaders gather for summit: in pictures President Donald Trump speaks during the bilateral breakfast EPA Nato leaders gather for summit: in pictures President Donald Trump gestures during the bilateral breakfast EPA

Speaking at a German Marshall Fund event on the sidelines of the Nato summit, Mr Trudeau said "we have to build that democracy and strengthen it," and doing so "is something that we believe in deeply."

Isis was defeated in Iraq in 2017, but Nato is concerned about the state’s resilience and leaders are expected to announce it will step up troop training and military academy building in Iraq, with hundreds of trainers operating out of the capital, Baghdad.