World leaders may have been quick to voice outrage over video footage of Libyan slave auctions, but activists raised the alarm months ago — and their warnings fell on deaf ears.

Aid workers, rights groups and analysts say they had been shouting about rape, torture and forced work for thousands of black Africans in the war-torn north African country until they were blue in the face.

But it took CNN's footage of young Africans being auctioned off near Tripoli, filmed on a hidden camera and aired on November 14, to force Western and African leaders into a flurry of condemnation.

OUTRAGE

United Nations chief Antonio Guterres was "horrified"; African Union chief Alpha Conde was "outraged".

France requested an urgent meeting of the UN Security Council, with President Emmanuel Macron branding the auctions a crime against humanity.

But NGOs and experts have charged leaders with hypocrisy.

"Ordinary people aside, everyone knew about this — governments, international organisations, political leaders," said Hamidou Anne, a Senegalese analyst at think-tank L'Afrique des Idees.

TRANSIT HUB

Alioune Tine, Amnesty International's West Africa director, said "hostage-takings, violence, torture and rape" were well documented in Libya.

"And we've been talking about slavery for a long time," he added.

Libya became a massive transit hub for sub-Saharan Africans setting sail for Europe after the fall of dictator Moamer Kadhafi in 2011 tipped the country into chaos.

The EU has been desperate to stem the influx — more than 1.5 million migrants have arrived in Europe since 2015, according to UN figures.

But leaders are at a loss to find solutions for the asylum seekers on the other side of the Mediterranean.

This month it faced heavy criticism from the UN over its training of the Libyan coastguard, which the world body's rights chief said resulted in migrants being sent back to "horrific" prisons.

'UNIMAGINABLE HORRORS'

With EU support, Italy has been training Libyan coastguards to intercept boats as part of a controversial deal that has seen migrant arrivals down nearly 70 per cent since July.

But the UN charges that the policy leaves migrants returned to Libya at risk of torture, rape, forced labour and extortion.

"The international community cannot continue to turn a blind eye to the unimaginable horrors endured by migrants in Libya," UN rights chief Zeid Ra'ad Al Hussein said.

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