What you need to know:
- It lays out 23 objectives to open up legal migration and discourage illegal border crossings.
- But the US and 15 other countries either opted out or expressed concerns, with some claiming the pact infringes national sovereignty.
- UN Secretary General Antonio Guterres sought to dispel what he called a number of myths around the pact.
A United Nations conference adopted a migration pact in front of leaders and representatives from around 150 countries in Morocco on Monday, despite a string of withdrawals driven by anti-immigrant populism.
The Global Compact for Safe, Orderly and Regular Migration – finalised at the UN in July after 18 months of talks – was formally approved with the bang of a gavel in Marrakesh at the start of a two day conference.
But the United States and 15 other countries either opted out or expressed concerns, with some claiming the pact infringes national sovereignty.
Billed as the first international document on managing migration, it lays out 23 objectives to open up legal migration and discourage illegal border crossings, as the number of people on the move globally has surged to more than 250 million.
Describing it as a "roadmap to prevent suffering and chaos", UN Secretary General Antonio Guterres sought to dispel what he called a number of myths around the pact, including claims that it will allow the UN to impose migration policies on member states.
The pact "is not legally binding", he said. "It is a framework for international co-operation... that specifically reaffirms the principle of state sovereignty.
"We must not succumb to fear and false narratives", he told an audience that included German Chancellor Angela Merkel, Panama's President Juan Carlos Varela and Greek Premier Alexis Tsipras.
Merkel launched an impassioned defence of the pact and multilateralism, saying her country "through Nazism brought incredible pain to humanity".
"The answer to pure nationalism was the foundation of the United Nations and the commitment to jointly searching for answers to our common problems," she said.
The pact, said Merkel, seeks to prevent, rather than encourage, illegal migration. "This is about safe orderly and regular migration – it says (this) clearly in the title."
On Friday, the US hit out at the pact, labelling it "an effort by the United Nations to advance global governance at the expense of the sovereign right of states".
It was the first country to disavow the negotiations late last year, and since then Australia, Austria, the Czech Republic, Dominican Republic, Hungary, Latvia, Poland and Slovakia have pulled out of the process.
Rows over the accord have erupted in several European Union nations, hobbling Belgium's coalition government and pushing Slovakia's foreign minister to tender his resignation.
From the United States to Europe and beyond, right-wing and populist leaders have taken increasingly draconian measures to shut out migrants in recent years.
US President Donald Trump has pledged to build a wall on the US-Mexico border and has focused his recent ire on a migrant caravan from Central America, while a populist coalition government in Italy has clamped down on boats rescuing migrants at sea.
Belgium's liberal premier Charles Michel won the support of parliament and is in Morocco to back the accord, but was left leading a minority government on Sunday after the Flemish nationalist party said it will quit his coalition over the pact.
Belgium is among a group of seven nations described by the UN's special representative for migration Louise Arbour as still "engaged in further internal deliberations" over the accord.
Bulgaria, Estonia, Italy, Israel, Slovenia and Switzerland also fall into this category.
The pact has been welcomed by the Catholic Church as an important step towards addressing migrants' needs and reducing their vulnerability.
"While some states have decided not to participate in the process or this inter-governmental conference, the Holy See is convinced that the enormous challenges that migration poses are best faced through multilateral processes rather than isolationist policies," said papal envoy Cardinal Piero Parolin, calling for its implementation.
The UN's children's agency noted that over 100 countries still have policies of migration detention for children, but said implementation of measures proposed in the pact would enable states to "better address the causes that uproot children from their homes".
Honouring the pact would "provide migrant children with better access to education and health services, and offer them stronger protection from exploitation and violence", said a UNICEF statement.
Other organisations, including Amnesty International, see the pact as just a first step towards protecting migrants.
It "is very aspirational in many areas, with limited implementation commitments," said Amnesty International's senior advocate for the Americas, Perseo Quiroz, in comments emailed to AFP.
After the Marrakesh conference, the UN General Assembly is set to adopt a resolution formally endorsing the deal on December 19.