Angela Merkel has hailed a new Franco-German friendship treaty as being a step towards the creation of a future joint European army.

The German Chancellor said the pact, inked in the ancient western German city of Aachen today, aims to build a 'common military culture' between the two countries.

In a speech during the ceremony, Merkel insisted the treaty 'contributes to the creation of a European army'.

The new accord was signed exactly 56 years after the 1963 Elysee Treaty, which set the tone for the two countries' close relationship following centuries of conflict that ended with World War II.

Both French President Emmanuel Macron and Merkel have pushed the idea of a joint European Army for the bloc that would be part of the wider NATO alliance.

US President Donald Trump late last year mocked both European powers by tweeting that 'it was Germany in World Wars One & Two - How did that work out for France?'

Angela Merkel (greeting French counterpart Emmanuel Macron today) has hailed a new Franco-German friendship treaty as being a step towards the creation of a future joint European army

The German chancellor (pictured with Emmanuel Macron today) said the pact, inked in the ancient western German city of Aachen, aims to build a 'common military culture' between the two countries

Merkel in her speech also said that, as France and Germany seek closer political, economic and defence integration, they should also work on a 'joint military industry'.

And she warned against rising nationalism in Europe as she called for a revival of cross-border cooperation.

'Populism and nationalism are strengthening in all of our countries,' Merkel told French, German and European officials gathered in Aachen's town hall.

Citing Britain's departure from the European Union and the growing protectionist tendencies around the world, Merkel noted that international cooperation is going through a rocky period

'Seventy-four years, a single human lifetime, after the end of World War II, what seems self-evident is being called into question again,' she said.

'That's why, first of all, there needs to be a new commitment toward our responsibility within the European Union, a responsibility held by Germany and France.'

Her words were echoed by French President Emmanuel Macron, who noted the 'growing anger' within European societies and pressure from without.

The Treaty of Aachen aims to boost cross-border cooperation along the countries' 290-mile frontier, but also improve coordination between the two nations when it comes to tackling international problems such as climate change and terrorism.

Both French President Emmanuel Macron and Merkel (pictured together today) have pushed the idea of a joint European Army for the bloc that would be part of the wider NATO alliance

Germany and France are often described as the engine of the European Union - to the occasional annoyance of other members, who feel sidelined by the cozy relationship between Paris and Berlin.

The treaty pledges stronger economic and defence ties and restates the countries' commitment to the European Union.

But it has been attacked by the far right, which accuses the pair of signing away their countries' sovereignty.

The leader of France's National Rally, Marine Le Pen, accused Macron of 'an act that borders on treason'.

One of the leaders of German's far-right AfD party, Alexander Gauland, said Paris and Berlin were seeking to create a 'super EU' within the European Union.

'We as populists insist that one first takes care of one's own country. But we don't want Macron to renovate his country with German money.'

The French presidency defended the bid to build up the 'bedrock' of the EU as being 'in the service of reinforcing the European project'.

Today's ceremony comes on the anniversary of a similar treaty in 1963, signed by Charles de Gaulle and Konrad Adenauer.

Germany and France are often described as the engine of the European Union - to the occasional annoyance of other members, who feel sidelined by the cozy relationship between Paris and Berlin

The new treaty aims to strengthen the so-called the 'Franco-German motor' that has been seen as the driving force behind European integration.

'We're seeing an existential crisis in terms of European integration, with Brexit and the expected strengthening of nationalists at the next European elections' in May, said Claire Demesmay, a political scientist at German research institute DGAP.

'In this context, confirming this belief in Franco-German cooperation has symbolic value,' she told German public radio.

Macron took office in May 2017 promising major reforms of the EU to restore faith in its institutions and quell rising populism.

But his ideas met with only lukewarm support from Merkel and other EU leaders, and Paris and Berlin have also differed on other issues including how to tax big internet firms.

The French leader's hand has also been weakened by more than two months of domestic 'yellow vest' protests.

The treaty commits France and Germany to closer military ties, including possible joint deployments - in the event of a terror attack, for example.

The two countries could also cooperate more closely on procurement, such as the purchase or development of new tanks or fighter jets.

And it includes a 'mutual defence clause' in the event of one of them being attacked, although they are already committed to this as members of NATO.

Macron sparked a row with US President Donald Trump late last year by urging Europe to reduce its military dependence on the United States, even calling for a 'real European army'.

Macron's critics on both the far left and far right slammed the latest accord as an erosion of French sovereignty.

A wave of false rumours have spread online that Macron was going to Germany to sign away parts of French territory to Merkel and that France will agree to share its permanent seat on the United Nations Security Council with its neighbour.

Some other European leaders have also bristled at the idea of an all-dominating 'Franco-German motor'.

Merkel in her speech also said that, as France and Germany seek closer political, economic and defence integration, they should also work on a 'joint military industry'

Italy's far-right Interior Minister Matteo Salvini has said ahead of the European parliament elections in May that he wants to challenge Merkel and Macron's pro-European message with a eurosceptic 'Italian-Polish axis'.

Amid the headwinds, German magazine Spiegel Online noted that while the treaty 'is full of good intentions, it lags far behind what is necessary'.

'After all the crises and upheavals of recent years, Merkel and Macron have failed to rekindle the fire of European enthusiasm.'

Business weekly Handelsblatt also called the contents of the treaty 'timid and fainthearted.'

Both the French and German leaders have seen easier times, with Germany already looking to a post-Merkel future after she announced she would step down as chancellor in 2021.

In France meanwhile, the 'yellow vests' have forced Macron to loosen the state's purse strings, throwing his deficit reduction drive off target.

Both leaders will speak at the signing ceremony at Aachen's historic city hall before taking part in a 'citizen debate' with French and German students.